Try the forum at the Chronicle of Higher Education website www.chronicle.com . You can do a search for old threads on this topic. The information on the likelihood of a British PhD getting a job in the US on there is depressing (and will make you very angry about the inaccuracy of the asumptions), but it might help you to target applications more effectively and avoid some pitfalls.

I think the relevant document is not the advert but rather whatever sort of contract you signed. If it's in the contract you have rights, if not you don't really.

I think the majority of people finish closer to four years than three, so it's the norm and better to submit a complete thesis that you are happy with than a rushed one. It's when you go significantly beyond four years that it's dodgy (eternal PhD student stereotype), although many universities now force submission after 4 years (not counting any interruptions of study), as this is one of the statistics they are monitored on nationally.

Moon I think treeoflife has hit the nail on the head. You want to avoid universities. That's where the issue is going to be very obvious. Non-academic employers are going to be more interested in your skills.

Solo what I think the problem might be is that there are substantially fewer postdocs available these days for science PhDs because of funding cuts. Anecdotally at least, there seems to be a pattern where unemployed PhDs are applying for research assistant jobs just to keep connected with science, and thus people like you get cut out.
Did you get on well with your MSc project supervisor? I wonder if you could ask him/her to be brutally honest about how competitive you are for PhD places, as someone who works in your field will know the precise funding situation, and what sort of cvs s/he are seeing for places in their lab. You could also ask about the industry side - where have previous students gone for example. You could also google DHLE statistics for your MSc - or ask your old university's career service where they display this information. It will tell you where the cohort before you were 6 months after graduating and might give you some ideas of new avenues to try.

Your university will halve the number of hours your supervisory team is given on their work load allocation to supervise you, so it might depend how overloaded they are already as to whether they can continue to offer the same level of supervision. Remember that you will need to fulfil a minimum period of candidature and that this will be longer if you are part-time, so will mean the time to degree is longer. All that said, a job opportunity related to your research is one you should grab, given how awful the post-PhD job market is, so definitely worth taking!

I think Hazyjane's suggestion is the best way to phrase it. I'd try to avoid the word doctorate entirely if you can. If you are asked about it, don't give excuses, unfortunately employers never like that. It would be better to brush it aside, with something like 'I've decided that academic research was not for me; these are the skills I've gained from it and this is how I think they'd help me be successful in this role, about which I'm very excited.' Concentrate on getting across the positive not the negative messages, even if that's not at all how you feel.

Diomedae,

If you haven't explored this already, could you talk to an advisor in the student union where you are? They have the advantage of knowing a university's systems & precedents but being independent. I'm thinking that it might be helpful to have someone like that present with you at this follow-up meeting to make sure everything is done properly. I'm very hesitant to offer any specific advice on your rights, as I think the regulations / policies are going to be quite variable from place to place, and maybe dependent on whether they have a policy on students being 'fit to study' or not.
While I agree it seems intrusive, if you and your GP feel your mental health is now being well-managed, perhaps submitting a letter from your GP saying that might be better than giving them permission to view your medical records. I think it's getting someone qualified to say things are under control that's crucial. I imagine the university and your supervisors are worried about how well at the moment, you will be able to deal with the inevitable criticism and need to rewrite that comes with the last stage of the PhD.
Alternatively, could you consider taking a leave of absence to recover? That might be worth suggesting if they seem obdurate about the MPhil.

This is very subject dependent, so I think I'd seek guidance from someone you trust in your subject.

Living abroad is challenging especially if you haven't done it before. Are you isolated for language reasons? If so, try signing up for classes, as it's a great way to meet other people new to the area, who will also be looking for new friends.
Very few places are truly boring but some are harder to get to know and to find things you'd like. The worst thing though you can do (speaking as someone who's done four different stints abroad) is to sit in your room bemoaning what you've left behind. Even though it often feels like the best option because when you're in a new country, even doing the simplest of things feels like running a marathon because you don't know how to do anything. On top of that you've started a PhD which is disorientating even in familiar conditions. You need to find a middle road between being kind to yourself and forcing yourself into action to find the things that can make this into a good experience.
If it's any consolation, it generally does get better and I would say to try to give it until Christmas, and then see how you feel. In the meantime, what is there to see and do in the city and in neighbouring places. Go sightseeing. Join some sort of club. What do you like doing at home and what can you recreate in your new temporary home? I would say that if you've come straight through bachelors and masters, even if you'd started the PhD in the same place, your social life would probably have not been as good because life as a PhD student is less 'studenty'. So you might have found yourself at a loose end anyway.
Finally on your health problems - couldn't you get the operation done where you are? Presumably there's some sort of health coverage there.

My blunt advice would be that with the exception of South Africa, don't do it, if you want to work anywhere other than the country you get your doctorate in (and then check that they hire their own graduates - some countries really look for N American / UK PhDs). Otherwise Africa is a large continent and the rules will vary from country to country and from university to university. You'd need to narrow it down for anyone to help you properly. The relevant embassy in London might be helpful.

Hi,
From what you post, it sounds like you'd be better just to break off your enrolment in Warsaw and find a suitable university closer to home. I'm assuming because you don't mention it, that there's no funding attached to Warsaw. I don't think a German professor would agree to supervise you for a degree in a different country and university - I also doubt that their university would allow them. The only way to arrange that sort of thing is through a dual doctorate arrangement (sometimes known as co-tutelle), but for that you'd need a proper supervisor in Warsaw too, as there needs to be formal agreement between the two universities. I know that German supervisors also use group seminars (Kolloquium) but I'm sure my friends who did PhDs there, also got some individual meetings even if they were not that often (every few months from what I remember).