I know of one prossie who was indeed studying to become a lawyer, but half way through the course she was chucked out for failing too many exams. However her Profile still claims a "University Education" - they do like to give themselves airs and graces.
I also know a couple of others who did in fact get their degrees, but both in occupations which had the rug pulled out from under them by reductions in government spending, and as a result both discovered that being a wg. was more profitable than the jobs on offer.
I imagine that there are probably quite a few very well educated prossies who just did a few tricks each week to help pay for their education, but who found, having got a degree, that being a prossie was far more remunerative than the jobs on offer.