I am still with the surgery (Waldon HC by New X station) I signed up with 20 odd years ago when living in Deptford. I briefly considered moving GP's when I moved to FH in 1991 but wasn't inspired by any of the available options.
My GP said he was happy to keep me on his books despite the distance as he sees very little of me and my family and hadn't ever been called out. Saying that, I rang him for advice when my son was poorly as a baby and GP turned up unannounced on his way home 'as I didn't usually ring for no reason so he thought he'd check as he was passing'.

I used to use the infamous surgery by Sydenham station in my younger years, it always seems to have looked like that! My boyfriend at the time caught chickenpox and our GP called in to check on him (as we were on his route home) for several days without being asked.

Looks like I've been lucky.