There's a number of really interesting suggestions in here, some of which had never previously occurred to me but which I'm now going to look into - particularly the idea of tutoring pupils from disadvantaged backgrounds. So thank you for the very generous and helpful response!
Again thank you for what is a very thorough reply with some very useful thoughts! I think in particular the idea of using the time to get used to, and to start to emulate, working patterns that will approximate what I come across in the TC would be very valuable - will certainly be exploring this idea further.
I'm getting this theme from the thread as a whole and it's much appreciated! It's easy for me to fall into the trap of feeling as though if I'm not filling every waking hour with something 'productive' (whatever that ultimately means) then it's time wasted. Of course, logically I know that's not true and I think the number of people who have responded here emphasising the need to relax and savour the time off while I have it will help me to do just that!
That said - I've found that the most 'relaxing' thing for me is being able to pursue some form of activity which feels work-like but which doesn't come with a load of associated pressures. For example, reading up on a practice area in my own time. So you needn't worry that I'm going to be forcing myself to work at the expense of having time to relax and look after my mental health - I've typically found the best thing for my mental health is to keep myself occupied and give myself these sorts of 'projects' to work on at a fairly relaxed and unrushed pace.
See my reply to the quote above - but, I certainly take the point! And will be bearing this in mind.
I really appreciate this insight into your daughter's experience and again, I will take on board the point about relaxing and pursuing broader interests! Starting the LPC right away isn't an option for me because I'm committed to the Law Centre at least until March (and likely beyond that, but the point being I have made a firm commitment to them to be with them for at least that long), and I don't fancy the thought of dovetailing LPC studies with full-time work.
Overall, thank you everyone for your replies, it has given me a lot of food for thought!