Rents are falling quite sharply in London to the extent that Bristol, where the University is located in a very pricey part of town, is possibly more expensive. (I am a landlord in London and wish I could achieve the sorts of rents DD and her friends pay in Bristol.)
My advice is to choose the course you like most and then make it work. The teaching during DDs intercalation year in London has been first rate. Placements are within commuting distance and no car is required. The University offers perhaps the best bursaries of any in the UK, and are definitely worth enquiring about.
The major cost differences are obviouly between the five and six year degrees. And there, to some extent it depends what sort of doctor you want go be. Stating the obvious, but a six year degree gives you six years of learning, or more specifically, three years of pre-clinical.
I teally dont think it is worth getting into the length of summer vacations. University vary a lot and it is hard to work out the
pros and cons of the different approaches. In practice those that need to earn work as HCAs in both term time and holidays and try to sort out placementsso they don'tneed to pay for accommodation. Vacations vary. DD had relatively short ones at the end of her first, second and third years as teaching went on go the bitter end and they had three week placements before the next ter started. This summer she gets three whole months, but faces finals this time next year. There won't be time to revise during clinical training so she plans to tackle the bulk of it now.
I was not aware that mumsneedwine lived in London. For many, especially young people, London is a great place to live, and there is a lot that students can do without spending much money. Each to their own, but please dont rule out some excellent medical schools based on an idea that London is unaffordable. Not least those applicants with a very academic profile may find their chances of gaining a place are higher at schools like UCL, QMUL, and Imperial than they might be elsewhere.