Eventually, when any RLDgets too mainstream and has actually brought tourists to the area, the big shots who have freebies try to close it down:
External Link/Members OnlyTalk about biting the hand that's fed them all these years....
I think discreet walk in parlours are a good option. Dunno about England but the 'intro' system could be upgraded in some Scottish places. Instead of paying first, or walking into a room of wordless EEs, I think the system adopted by many countries is quite pleasant. Basically walk into a reception area, then receptionist calls and introduces the girls, who walk in one at a time, kiss on the cheek and handshake. Then when they've all gone back to their backroom closet, asks the punter which, if any, he wishes to book.
Another option would be to have semi-open brothels (Geneva has a couple on this model) where there are 2 or 3 resident hookers often discreetly trying to entice people in (laid-back version of the Thai/Asian 'come-inside' girls) but the place is also open to street walkers who pay a fixed fee if they come back with a punter. At least it lets SWs to operate safely side-by-side with brothels.
The drugs+crime problem and other legal concerns are readily tackle-able once the selling of sex is decriminalised as long as it is the right setup and monitored in the right way. Geneva and parts of Germany have some good examples.
What often happens, once you eliminate forced trafficking / forced prostitution and the other immoral aspects is that criminals see punters as easy pickings. Fluffys or simply idiots wander round with beer goggles or in a rose-tinted haze making easy pickings for muggers and pickpockets.
The answer is for punters to be or become as aware as they would in any situation that isn't minutely controlled.