One of the things I discovered during my PhD is that I actually am stupid. Once I'd made that discovery, looking stupid wasn't really an issue. Luckily time and persistence was enough to compensate for stupidity, and I eventually attained my PhD. Which I'm particularly proud of, given what I had to work with.

I just had a room in a student house for the 4 years of my PhD. I paid around £300 a month plus bills (although the landlord paid for the TV licence). There were 3 of us most of the time, mainly postgraduates, though for my last 2 years I shared with one female PhD student and one male undergraduate. We all had our own shower rooms (big plus!) and managed to make the shared kitchen work without any issues. I was in my late 50s/early 60s, they were in their 20s, but I think we all felt it worked pretty well. Maybe I got lucky, because all of us were focused on our work and there were no riotous parties.

I got a funded PhD in biosciences at the age of 58, so it is possible. Like you, I was only doing it for interest.

Ah, we called it 'journal club'.

Can the university where you did your MA issue an academic reference, rather than a specific person? This is what happens with the Open University, because students rarely have actual face-to-face contact with real people.

When I joined my lab, along with two other PhD students, there were no postdocs! The lab technician showed us the basics, and in the one area where I felt I needed more training I booked an external course. This was entirely self-funded, as my supervisor's reaction was "What can you possibly learn outside that we can't teach you here?" In the event, I learned a lot!

My university had a form to be completed for an extension, which had to be signed off by me and my supervisors. There were only a limited number of grounds for an extension, and anything medical had to be accompanied by a doctor's letter.

I wouldn't worry unduly. My situation was much worse, I did some last minute amendments to my Figures because conversion to PDF was corrupting some of them, and ended up with the wrong x-axis labels on all the Figures from one chapter! So you can imagine how I felt. Anyway, I had a chat with my supervisor, who asked me to print out corrected Figures, which he then forwarded on to the examiners. I also had a substantial list of typos and minor corrections which I handed to the examiners at the beginning of the viva. They were quite surprised, because they had only spotted a few. In any event, it didn't seem to be a big issue, and I passed subject to minor corrections. By the time you submit your thesis, you've read it (wholly or partially) so many times that it can be hard to see the wood for the trees, so I wouldn't beat yourself up about it. By the time I'd completed my corrections I had found even more typos, but the important thing is that the final version of my thesis, which will be available for the world to see, is (hopefully!) a typo-free zone.

I agree with Dr Jekyll, I used R for just about everything in my biomedical PhD. It was not generally used in our department (they tend to use SPSS), but we had an introductory lecture from a postdoc in the department and I was hooked. I started with a very thin volume (just over 100 pages) called "Getting Started with R: An Introduction for Biologists" by Beckerman & Petchey, which I read from cover to cover, but thereafter my main resource was CRAN and Stack Exchange. I bought "The R Book" by Cawley and "Discovering Statistics Using R" by Field, Miles & Field, but hardly referred to them. I had to consolidate and manipulate data from over 100 spreadsheets, so R was a Godsend. The original data were never touched, thereby avoiding the risks of copy and paste type operations, they were simply loaded, manipulated, then exported to new CSV files. It's certainly a steep learning curve in the early stages, but well worth investing the time.

I've just completed a laboratory-based biomedical PhD after obtaining a similar Open University BSc to you (actually a BSc Life Sciences, but it contained a mixture of biology and chemistry modules). I would reiterate what others have already said, it's going to be very difficult, if not impossible, to find a distance learning PhD in the biosciences, as most projects involve a substantial amount of laboratory work. Part-time PhDs are certainly possible, but would be dependent on the nature of the research, and funding might be a problem. I did a Masters first (an MRes to get the necessary laboratory experience), and then got a fully-funded PhD (in spite of being in my late fifties!). I think a similar strategy might be your best bet.