I have had exactly the same snag. Found it to be a "pin prick" hole in the radiator,which obviously sprays water out under pressurethrough the front grill.
Short term cure was by using "Rad-Weld" but this has now finally given up after a further hole appeared in the Radiator fins.
Have just purchased a replacment Rad. from "Advanced Radiators" 0191 267 3312 (Next day delivery). Excellent price, compared with some quotes i received.
Graham Barnes, July 2008