Entry for degree courses straight from school is competitive and there are minimum academic qualifications. But after a few years you become a prospective "mature student" and universities take other things into account - they use terms like "experiential learning" and "self development" but what they are essentially getting at is that a few years of living, travelling and working can go a long way to compensate for the lack of formal Level 3 quals. If they have any doubts then they offer you a "foundation degree" (which is a one-year course from nothing to to a Level 4 standard). Once you have passed that you can "top it up" with a 2-3 year course to a basic or honours degree (these durations are for the full-time version - part time .durations vary).
It may sound strange, but it can actually be easier to get on a course at Masters Degree level. A large proportion of Masters-level courses are taken by mature students, and the entry requirements are usually extremely flexible. 25 years ago you could only take a Masters as a second degree, but times have changed and I know many people who have gained MSc/MEng qualifications without a first degree. There are a huge number of part-time tutored Masters courses available (most universities offer them) so it's just a matter of picking your subject. Although they are "tutored" there will always be an element of research to deliver a dissertation or thesis, and while this can be a lot of work (if you choose too broad a subject) you have tutors and supervisors available to guide you. IIRC the usual stipulation for a part-time masters is that you have to show progress or "gain credit" every year, and you must complete no later than five years after starting. Some full-time Masters courses can be completed in a year, but that's often a fast-paced course which needs a lot of effort.
PDR