So, what would you need to do:
1)Establish/gain entry qualifications (the 4 yr GEM schools would tend to want a more recent more relevent degree)
2)Actually gain a place at a medical school - will your family be able to move if the only place you get is at the other end of the country? Because if you only apply to your nearest place, the odds of getting in are pretty well zero
3)Fund the course. You'd need to check against your circumstances, but pretty standard med school course fees are £9000 per year for the first 4 years. That is, of course, separate from text books (expensive), kit (expensive), travel costs etc
4)Get through medical school. Talking to todays's students, their friends doing other courses still get days off etc. Medical school is basically 9 - 5 Mon - Fri in the first couple of years (with quite a lot of extra work to do outside those hours), then when you go clinical the hours get longer and more unpredictable, rotating between hospitals across the region. Oh, and the exams really suck.
5)Survive foundation years. So that's 2 years of being sent to a new job, often in a different hospital (or sometimes GP practice), every 4 months. With little choice about where you go. Needing to very rapidly learn new skills in each of those. Need to leave on time to make dinner for your kid doing GCSEs? Not if a patient got sick at nearly home time. Tonight's your child's birthday? Sorry, the evening person rang in sick. (Yes, childcare gets considered, but the patients have to be treated, and the person who has a toddler to pick up will get higher priority than you). And, of course, your first experience of working runs of high intensity night shifts. In your 50s. When your family could be living hours away. People die commuting in those circumstances...you might not see your family for a fortnight, to avoid dying on the roads.
6)Then you need to get into speciality training (and survive it). That's another 7 or 8 years if hospital, 3 if GP. Even if heading for GP, you'll still be doing those horrible runs of nights/weekends for those 3 years. If hospital, you'll be doing them all through training...whilst changing hospitals up to every 6 months, with ridiculously short notice (don't get me going on my medical staffing department rant). Whilst in your own time spending many hours on eportfolio tick box exercises, and many many many more hours working for some truly horrible exams. Which you will spend more thousands of pounds to be able to take.
7)Yay! You're ready to be a GP, or a consultant. Hate to say it, but that's when it really starts getting crap. The burn out rate is appalling. As is the rate of depression, divorce, suicide...
I currently have a trainee who is 40. So he started med school at 32. He's totally exhausted, compared to his younger colleagues. I have taught medical students in their 30s, who had a science background. It wasn't the academic stuff that caused them a problem. It was fatigue, and having so little control over their lives.
Ultimately, the choice of whether apply is down to you. But if you decide to do it, please go in with your eyes open. And if you really do mean to do this, then you've got better odds of surviving the experience if you don't wait another 8 years....though the impact on your family....not easy.