[turboboy]

Just to follow up on this I tried adjusting the cable at the lever end in the passenger compartment and although there was some slack which I managed to reduce, it did not resolve the problem.

Searching t'internet I came across an American site where someone had found the rubber blocks fitted to the underside of the front of the bonnet were not pressing up hard enough and needed replacing.

After a bit of experimentation I stuck a piece of 5mm thick sponge sheet on the near side rubber block and the bonnet now releases properly every time.

(Tried to add photographs to explain but upload didn't work).