Would rather defer foundation training than leave London - what are my options?

I'm a 4th year on a 5 year course and may never need to worry about this issue, but I want to be prepared for the worst. I'm in my 30s now and have completely uprooted my life for my education several times, but now feel settled in London and have no intention of relocating again.

Naturally I'll be selecting the 3 London deaneries for the foundation programme. I assume you have to select a 4th and 5th deanery and can't just leave them blank (please correct me if I'm wrong), but I'd have no intention of leaving London if I bombed the SJT in any case. I'd rather wait a year and reapply but it's surprisingly hard to find out if that's an option, perhaps I'm using the wrong terminology. Can you simply take a year out after uni to reapply if you're not happy with your deanery? I'm single and have no kids or special circumstances that would keep me in London unless matched by the normal ranking process. I'm considering applying for the AFP, admittedly only for the control it would offer over where I live.

I'm serious enough about staying here and maintaining my social network that I'd consider leaving medicine if it would require me to relocate again. As far as career planning goes I'm fully committed to being a GP so don't anticipate having to worry about being forced to relocate again after FP, but I've come to appreciate that there are things more important to me than my job. Maybe this is incompatible with being a doctor but, if it isn't, I'd like to know how to navigate the foundation programme application process in the hypothetical situation above. Thank you!

Yes you can apply again later. There is a time limit - you must start within 3 years I think.

Have you seen how big the South Thames deanery is? Or some of the commute times you may be facing even within NWT?

Great to know, thank you. Yeah, I know commuting can be rubbish even within the London deaneries, but even throughout large stretches of South Thames I'd be within 1.5 hours of central London if I pick where I live intelligently. I'm not even bothered about moving property every few months, as long as I can maintain my local hobbies and relationships.

Yep, as said you can withdraw and reapply, but you may still not get london?
However, EBH has some v commutable hospitals- tho 1.5 hours isnt v commutable in practice when you are tired.
Maybe look at priority programmes as well as that nails the trust you are going to be in - which can be nice to know early.