Hi pandh,
Ah, but are the LAX and PHX Zones Class A? No, thought not! And there are vast differences between UK and US ATC philosophy - ask any UK Commercial pilot which methodology he prefers.
Looks like you guys had better have words with your flight instructors as there seems to be a big hole in your/their knowledge and experience of SVFR in the London Control Zone. If I had the time and sponsorship I would arrange roadshows to educate you all.
I also happen to know that Flyer magazine organises visits to Heathrow on odd occasions..... enough said?