A prospective employer wants to know what you are like to work with; ask someone who worked with you and had a positive experience of doing so to be a referee. Don't assume, though, that because they nodded and made sympathetic noises whenever you let off steam that they felt the same way.

Unless you also worked for the university, then I doubt if HR would be involved at all. As a student, any request for a formal reference would go through the Admissions, Registrar, Senate House, or "Student Records" department. If one of the supervisors asked someone in HR for advice then, as is implied above, they would probably tell them to say the bare bones and nothing else. If they say anything bad and can't substantiate it then they are theoretically laying themselves open to an accusation of defamation.

I'm sure that you thought all this through before you made your complaints and demanded an apology letter.

If I was a PI and considering offering a role to a recent PhD then regardless of the names on the application form, I would check who their supervisor(s) were and pick up the telephone and have a chat with them. It is a way of networking and building relationships across the field - your former supervisor might be asked to vet one of my grant applications, or review a draft publication, after all. There's not a lot that you can do to prevent informal conversations between peers from happening.

Similarly, if I was a supervisor and a former student said that they were going to apply for a particular job, I might well give the future PI a call to "touch base" and say how excited I was to hear that my former student was going to be applying and that I will be delighted to give them a glowing reference when the time comes. If the number of applicants exceeds the number of places [when doesn't it?] then who are the ones that are going to get short listed?

Good luck.

I'm about to commit to a two-year part-time MRes in Photography. I'm a (very) 'mature' student but am keen to get the most I can from the experience and for my money! I'm wondering what kinds of support / encouragement / facilities to expect from them? I'm fairly happy with my supervisor (who is quite senior) and know that I will get my fair share of their time. But what about facilities such as printing, help with publications, involvement / attendance / participation in undergraduate and taught masters programmes, networking and access to common rooms, study space other than in a library? Any thoughts, tips etc would be really appreciated. I realise a lot depends on me and how prepared I am to put myself out, but anything specific? Thanks in advance.