Thanks guys, appreciate the nice comments.
Yagi - I tend to use mostly the corona Sun and Sky for this blown out effect. Its not a particularly complicated way but i usually leave most sun and sky settings as they are and then expose for indoors and increase the highlight compression until just before i see detail in the sunlight hotspots.
ACGI - Thanks mate, glad you're a fan. I usually always have an RGB value for white walls of 255, however having pure white causes problems and slow down in rendering so i reduce the 'level' value to 0.8 to reduce the brightness slightly and make things good with the Albedo again. This is essentially the same as reducing the RGB value to something like 200.
Iain