Exiting systems are supposed to exist under the Nordic Method, but realistically if you can earn £150 an hour (not an uncommon rate for independent sexworkers, £100 is certainly achievable by most) with total flexibilty as to the hours worked, why would you want to take on a NMW, possibly zero hours contract in a "respectable" (and, of course, totally non-exploitative) job?
Migsy isn't underground, her pimp advertises her services on her behalf. In, y'know, public places, possibly including Adultwork. It's not the '60's any more, it's not business cards in phoneboxes, and "word of mouth" wouldn't get her 5-10 punters a day of any age these days.
And yes, stigma from radfems, who refuse to recognise the agency of adult women, who call women who are brave enough to stand up and speak out "non representative", who refuse to read Dr Magnanti's book on sexwork because she was, erm, a sexworker...