Loose I am in my 5th yr of working as a doctor, and was single and childfree throughout my training. But, just in general terms.
Starting salary is £28,000. Now at year 5, I get closer to the £45000 but only because I do nights, 1 in 10 evenings, and 1 in 4 weekends. And that is an easy going rota, there are much worse out there.
Moving around - depends upon where you study. In Wales, you could find yourself 5+ hours travel away from the uni city. Bristol placements on the other hand, could be commuted to from the city every day. Something to bear in mind though.
And yes, in the future, you will discover that the regional employers care not one jot that you have children, a house or a life - and will be expected to move all over the place on a regular basis, until you get a bit higher up the ranks.
It is very rewarding, but very very demanding. I wish you the best of luck in whatever you decide.
And fwiw, I would do nothing else, it is the best job in the world.