Having quickly looked through this, it looks like some people are quite worried about the whole application process. But you really don't need to be, getting into medical school isn't actually that hard, unless you want to go to a place like bristol, you don't need to have done much, I got into medical school without playing an instrument, doing DofE, going to a foreign country etc. Literally, a 1 week shadowing placement, a year or 2 of weekly volunteering with people, and something that shows you can work in a team and something that shows you can relax is enough (kill 2 birds with one stone and do a team sport).
With regards to work experience, teaching hospitals in big cities offer placements to loads of students on a weekly basis, london in particular is a good place for shadowing experience, I literally just applied to St George's for a placement, had to write a short personal statement thingy, and they gave me a placement in the trauma and ortho department, I was in the A&E while they were filming 24 hours in A&E, and I didn't have to do anything special to get such a good placement.