From what I've understood seeing others remarking on how it works over the years:
1) There are fixed national payscales for these when in training (foundation and GPST) - it depends if you're in England/Wales or Scotland/NI I believe. You can see them here:
https://www.bma.org.uk/media/7509/pay-and-conditions-circular-md-4-2023-final_0.pdf . Once you get CCT as a GP it's a bit less clear cut as if you become a salaried partner in the GP surgery I think it's a bit more complex how it gets worked out. Also if you just work as a locum GP then it'll be whatever the locum rates are presumably?
2) My understanding is GPSTs have to spend at least 12 months (and potentially up to 18 months working in hospital based rotations. These do not need to be consecutive rotations (although might be). I think they can be in various specialties that you may rotate through in a hospital e.g. A&E vs ward based specialties? After you complete the GPST though I don't think there's any hospital based work unless you choose to develop a special interest in something involving a hospital based clinic?
3) I believe if your hospital rotation has a call rota then you work this as a GPST. Not sure how that works once you are a CCT GP and working in a GP surgery - I think some have late sessions or weekend hours that run so they might have a rota for that, but I think it's less out of hours in the sense of 2am call outs?
4) I think in theory it's something like this when you qualify although I think it's more like 8-6/7 with minimal (by hospital specialty standards) weekend working? As I have heard it's rare to truly work 9-5 due to high demand in surgeries for extended hours (most other people seeking a GP appointment probably also work 9-5!) and admin requirements of the job.
5) The UK has statutory annual leave allotments so it will be the legally required leave you are entitled to, unless purely locumming (in which case you don't get holiday but you can just choose not to take shifts for a while if you want). More here:
https://www.gov.uk/holiday-entitlement-rights . You may accrue additional days through seniority as a trainee or through agreement with the practice as CCT GP, depending on exactly how you are working (whether a salaried partner in a GP surgery or not might change that?).
This all assumes working in the NHS after training though. If you work as a private GP after completing GPST or go and do something different e.g. maritime medicine or something, then it'd be whatever the employer offers!
@GANFYD can probably a lot more specific detail to this though!