Private hire and hackney carriages come under local licencing authorities, their priorities on the road differ. Any vehicle can as has been discussed on here at length in the past, stop long enough to pick up and set down passengers. If the OP is doing either of those then he should be ok, what he can't do is wait for his passengers for too long! Providing his passenger is pre-booked I don't see a problem. If he is waiting for a fare on the off chance, that is illegal, private hire passengers MUST pre-book through a licenced operator.
Hackney carriages (back cabs), taxis, can be hailed anywhere and can wait in taxi ranks.
And yes, he should know the rules.
