I just phoned Kenlowe up to see if I could get one of their silicon seal thingies that go into the rad hose where the sensor fits. Straight through to someone who knew what she was talking about, they're sending 2 out in the post tonight, and next time I'm in the post office, if I could send them =A32.50 in stamps to cover the cost.
Not to common to get service like that :-)
AndyC.