You are far from the only retiree to move over to France. While I'm not British and not retired (yet), the "welcome group" I am part of has LOTS of British retirees or almost-retirees. Granted, we are closer to Paris, but the overall association (AVF) has 300 or so groups scattered throughout France. Check the AVF website to get a feel for areas where you can meet up with other newcomers (French , British and all other possible nationalities - this isn't an expat club). AVF -- Accueil

As for the "tax matters" - the key one is that once you become resident in France, your estate will be handled under French law. Period. I do know a couple of Brits who are planning on going back to the UK on retirement because of concerns about French inheritance law.

Basically, when you die as a French resident, your estate will go to any and all children you leave behind, and if there are none of those, then to your parents (if they are still around), then to your siblings. If, like me, you have none of any of those categories left, then to your cousins. (I leave out the spouses, since you said you are single, but spouses are not terribly well provided for in France, though they can avoid paying the inheritance tax.)

The tax threshold is pretty low, so if you're leaving lots of money, your heirs will pay. But, if French law pretty much leaves it to those you were planning on leaving it to anyhow, you avoid the hassle and expense of making a will. (Wills in France are only good for whatever portion of your estate is left over after the State gets through making its allocation.)
Cheers,
Bev