bored, mature students are usually welcomed, but I would aim for one of the more "modern courses", rather than Oxford/ Cambridge. I'm presuming you'll need a course as close as possible to your home, so start investigating NOW. Find out requirements and expectations and about the design of the course. TBH, at your age and with your background, I wouldn't bother with a course that does an intercalated degree, and at some places they're compulsory, so you need to be sure where you're aiming for. Your application will be looked on more favourably if you have direct "hands-on" experience of patient care, so if you can, volunteer in a nursing home, or something like that, and do it now, and regularly. That sort of commitment will impress the aplications people. Your academic qualifications are not in dispute, but you will be up against MANY 17/18 year olds with 5 A levels, who've been volunteering during their 6th form years.
Assuming you get in, you'll probably find the course a breeze, BUT as things stand at the moment, you would struggle to get into surgery, especially orthopaedics. Things may improve, but medical training has had a major overhaul recently and it's not a happy place to be (I mean postgrad training). If you straight from graduation into Foundation years 1 and 2, you then need to get a place on a surgical training scheme, which is at least 6 years long, depending on specialty chosen, and you HAVE to make your decision then, during FY2, before you've even worked in the specialty .
Another thing to consider is that medical training is (relatively) family-friendly, but work on the wards and in surgery isn't. Yes, they have an obligation to train you flexibly, if that's what you want, but in practice, the system doesn't work very well, and you will have to plan your family life with military precision- you cannot leave a sick patient in the throes of a heart attack because you need to pick your child up from school, and you won't necessarily be able to get your leave during school holidays, and you will probably work through Christmas....you need at least two fall-back arrangements for each day that you are working!
Having said that....if you want to do it, go for it!