I don't think this thread has much further to go but it should be remembered that it was all about visits to the Flight Deck on SQ flights.
The rules are probably not the same as on domestic flights within one's own country or close neighbours.
A majority of SQ is long and medium haul with turn arounds that simply don't lend them selves to flight deck visits. I applaud the posters here who can always find time for visits, (Geebz etc.), I do though wonder what their cabin crew, traffic staff and engineers think about it as everyone struggles to make a slot time.