HI!
I only have knowledge from my own experience, but I shall try to help.
Applying to an actual university right now might end up being really difficult. What you could always do is apply to courses at an actual college (a non-selective, vocational/academic school) and work through earning qualifications.
There's also the open university which is at home study, but I can't imagine you'd want to do that seeing as you're only in London a short time.
The main universities in London are:
UCL
King's College
London School of Economics
South Thames
Westminster University
And the Royal Colleges, which are for medicine and music.
You might want to have a go at ringing some of these schools right around the end of August when Clearing
http://www.ucas.ac.uk/students/nextsteps/clearing/ (click for more information) happens. Be ready with your application and details though, because they need to make a lot of these decisions quickly.
IF, however, you decide not to do school, there are lots of places which take interns and part-timers, especially (WAIT FOR IT) in this economy. You've got the upper hand in being a nurse, a job high in demand (whereas I am a humble and unemployed scholar)
Can't wait till you get here. PM me your details and we can meet up.