Its not just The UK I don't think they are for sale full stop, US or anywhere.
There doesn't seem to be any hard info about release dates, however these two comments are from a US store
"We still do not have an ETA quite yet. According to our latest info from Intel, the G0 Q6600's have started shipping, in limited quantities, from Intel late last week. They are expected to be very tight for a while, which means they will be fairly hard to come by at first. We're currently working every angle possible to secure these chips. It's a very difficult process for us to ensure we get the new chips, as most of the distributors and suppliers still have a lot of existing B3 inventory."
and
"There is strong indication that we will begin filling orders around August 6th. This is not yet set in stone, but preliminary reports from one of our major suppliers says that our order has been allocated, and will be filled the first couple days of next month. While this is not yet guaranteed, all signs look good so far".