The cold tap is absolutely fine, superb pressure, had to turn it down at the isolator by the tap to control the flow as it was too much fully opened.

Tiff - your right mate the flexible hose suppled with the tap does have a smaller fitting going into the tap, thought it wouldve been a conventional size though (see ebay link for tap further up!).
Just bought a full bore isolator so will try that and see what happens!