Hi i'm 28 and I'm currently doing a engineering foundation year, and before that I did an access course.
I think recent academic experience is a must as its quite challenging, you don't realise how hard it is to get back into studying until you try, and I would say that thought is echoed by all the mature students on my course. Maths in particular is quite challenging after a 10 year break.
I definitely recommend doing a foundation year and if you have at least a B in GCSE or equivalent maths you shouldn't have a problem getting on to one (even if like me you got it 10 years previously) Being a mature student is an advantage in those respects. But if your maths is still good (A-level good), then showing evidence of that will probably help with first year entry.