Picked up mine on Saturday from Sevenoaks try the Glasgow store They seem to specialise in Yam amps
Other places are waiting till Yam announce whats going to happen in Feb including a possible price increase 
Cant seem to find this amp ANYWHERE, anyone know where I can find one ?
Could also try Exceptional-AV.co.uk : : Specialists in Onkyo's award winning Hifi and home theatre systems ...
I spoke to someone there the other day who said they were getting in a few dribs and drabs and were expecting some more this weekend. You may be able to reserve one? Price they were quoting was also good £283 but not sure if that also includes delivery.
I put my order through here on saturday, gave them a call today as there had been no update on the order status, they confirmed they have 8 or 9 in stock, mine should be sent tomorrow. Bloke I spoke to said there had been some probs with the online order system, but would look into it and call me back.
Probably best to give them a call if you want to order one, they're not the quickest to answer the phone, may take a couple of trys to get through, but at least they have stock! The price is slightly higher than PRC, but still good value.