Why would you do that.
If you have a 110k paying job, I assume you've already done your pre-uni qualifications. So I see no point in you doing A levels, it'd be essentially redoing what you've already done.
I think you're slightly confused about the British education system, because of the wording. For example, when we say "College", it doesn't mean the same thing here as it does in the USA.
A levels are pre-uni courses. Bit like your idea of a high school.
A levels will not qualify you for a grad job.
You do A levels at Colleges and Sixth Forms.
You do University courses at university. What I mean by that is, "Going to college" in American stance isn't the same in the British education system.
Overall, the British edu system goes in level:
Level 1 (Low graded elementary GCSE qualifications (E and D grades))
Level 2 (High grades at secondary school GCSE qualifications (A* - C grades))
Level 3 (Pre uni qualifications and apprenticeships such as A levels which you do at college or sixth form)
Level 4 (Bachelor degrees and advanced apprenticeships)
So if you're keen on doing something academic in the UK, you should be aiming for uni courses, not A levels.
To apply to, or research, level 4 courses in the UK, go to
www.UCAS.ac.ukG'luck
P.s. I'm very sorry if I sound patronising in this: I'm assuming that you've been to school in the US and that you're not sure about the british edu.sys.