Daisy, I am so pleased for you as you have got so much support here aswell as having a good network of family and friends, so that you know that if you ever found yourself stuck, there are many many folk who would be more than happy to help you out. That should give you huge peace of mind, even though I sense you are the kind of person who will only reluctantly ask for help, once you've had a damn good try at sorting yourself out but have had to grudgingly admit you need some help.
Go for it girl, you may never again get the opportunity. Getting my van 6 months ago has changed my life, I'd never considered living on the road, but it's something I now think about regularly and I am looking at my life and wondering what I can do to make long term changes which would put me in a position to be able to consider it as a viable option.
I have a hidden disability which doesn't affect me much physically other than chronic fatigue & migraines, which mean I need to get plenty of rest, and a dependence on meds and support, which I have to be organised about (ie making sure I order and pick up prescriptions regularly etc) and I am finding that I have a better daily routine in the van than I do at home, I eat better, I sleep well, I stress much less, and I spend more time just "being" and being mindful and enjoying life.
As the NHS's new computerised record systems become more integrated and reliable, you should find that any GP will be able to access your medical records etc online, and all GPs are supposed to treat visitors to the area, regardless of where they are registered.
Live the dream Daisy, follow the sun xx :goodluck:
edit : A disability support dog, trained to your specific needs, is worth thinking about. The companionship and security that a dog gives is something I wouldn't be without, and I don't think I'd wild without the dog.