I was at Heathrow in 1975 and I don't understand why yoiu should think that only a procedural controller would ask an aircraft to squawk ident? That is a radar function and only a radar controller would issue that instruction. "Director" is a 100% radar control function
I think what he means is that the aircraft came to 'Director' from a non-radar unit, after which 'director' asks them to squawk ident...