Well it appears that in Britain there's no requirement to fly standard altitudes if VFR.
In any event quadrantal is not an international standard, just the British way of doing things. I know that in Australia it was discarded a long time ago and replaced by the ICAO system.
I don't want to seem jingoistic or offensive in any way, but the more time I spend on this forum the more convinced I become that British aviation is a bizarre little realm of its own, quite remote from the rest of the world.
I can assure you that in other countries there are standard altitudes, and they are flown.