I think you should check - you usually need a National Insurance number in order to get a job - this is what they put onto the forms in order to pay you through a payroll service. NHS number is a national health service number which enables you to get free (or cheaper) medical stuff.

Getting a job - look at the Evening Standard newspaper - loads listed in there, also in the Guardian newspaper, check Ms London or Girl About Town and the Metro also. Don't know if you have a learning centre or library in the university but they often take on staff and may have the opportuntity to work in the evenings, we used to do this at the Further Ed college I used to work in. Otherwise you may be looking at waitressing, stacking supermarket shelves or bar work (none of which pay particularly brilliantly). Sometimes people get work doing things like data inputting or photo manipulation and these are sometimes evening. Could sign on with an employement agency, Brook Street, Reed, Talent but there may be ones more specialist in your area. Can you teach? Could have get evening teaching work at adult or FE colleges, or tutoring? There are agencies for these too.

You might need a CV (resume) no longer than 2 sides of A4 detailing previous employement, education and skills with a couple of referees.

Sorry, didn't mean to write an essay. :-)