Cannondales are really expensive in the UK, where we get price gouged by multinationals.
I recommend you find a nice Kinesis frame. They are UK designed and have good forks.
http://www.kinesisbikes.co.uk/
Alternatively, a lot of the bigger retailers have their own brand frames. You could look into Ribble, Dave Hinde, Merlin etc. Amazingly, you are not far off the entry level British made frames (eg Bob Jackson). Otherwise, hit ebay.co.uk and type in names from a list of Italian builders and wait.
If you want a complete bike, 2nd hand or Decathlon or Saracen.