My supervisor's grant is running out and he wants me to write up three chapters; but I'm not even a third of the way into my second year of PhD? I do have enough data (just) and I have funding to pay for bench fees in my third year. What to make of this situation?

It depends on your project, difficult to say like this, but as example, I did my PhD in 4 years part-time, and wrote 4 out of 9 chapters during the second year (my sup wanted me to have the 4 chapters ready for the upgrade exam).

And at the end I was very glad to have half of the thesis almost 'ready to go', and not to have to write everything. So, in principle, if you have done the work and have the data, I don't see a problem with writing up some chapters. This does not mean that you have then to finish this year! You just start writing up what you have so far, and then move on with your studies/exps.

Am I right in assuming that the first two chapters would be lit review and methodological considerations, and the third would present the first bunch of data you have?

xxxW

I think it depends on your PhD - what type of PhD is.

The more you have written up the better. For me however, though I am writing up the methodology chapter as as I go along and the study chapters too, I am leaving the detailed literature review right to the end because research in my area is constantly growing, so it makes more sense to write it up formally in the end, or else theyll be too much editing to do in the end.

Writing up as you go can be a good thing. However, some unis will not let you submit before a particular time point e.g. 2.5 years. Unless things have gone exceptionally well you may not have enough data/material for full thesis at this point. I suggest seeking advice from a postgrad tutor in your department/faculty.

I wouldn't say my project has gone exceptionally well, but it's not too bad. Right now I have almost enough data to write three results chapters, but because some of the results are negative and my work is not yet published, I feel writing up a full PhD thesis is a stretch right now. I'm basically a year and a bit into my PhD. I would have enough to pass the second year viva or transfer to a masters, but probably not a full PhD right now.

My supervisor does want me to write three results chapters, not intro/methods/first results chapter. Perhaps he just wants to see where I am, but with his funding ending and his job in a flux, I am concerned for my future.

My funding does run for three years even if he leaves. So I'm thinking the best approach is to get my second year viva out of the way before his potential exit, so that the department is obliged to find someone to babysit me during my third and final year.