The car has been running warm/hot this summer. Suspecting that the radiator was to blame as the outer edges never heated to the same extent as the centre I followed the advise on this forum and timed how long the radiator took to drain. At 25-30 seconds I think it was a safe bet to be the cause so I went ahead and followed the next recommendation which was take it out of the car and flush it through with CLR. It worked a treat and it now empties in under 10 secs so the diagnosis appears to have