I would second Oxford Pram Centre, fab, fab c/s. our front wheel was faulty before we could even use it, we live 2hrs away from oxford pram centre, i was in tears as didn't know how to take it back!! The v.next day before midday OPC had couriered us a complete new wheel fitting with full instructions they are fab!
I bought a sport + doubles + raincover and sleeping bag (or you can have cocoon) for £389, without the cocoon/sleeping bag they are £354.99.
I was in Mothercare today looking at double pushchairs. The assistant told me that they were getting them instore and there may be a promotion where you get certain bits free (the bit to make it a double?). She didn't know when that would be on but I'm going to keep my eye out for it.