Final instalment of the mystery rattle, thought I had found it with the airbox tapping the bonnet, so gentle filed of the bonnet edge to give better clearance, but alas after test run was still there, returned home, lifted the bonnet and it rattled, closed it and it rattled, head scratching time, the hinges had always been oiled, along with anything else on the car that moved. I noticed that the rear hinge was a bit jerky, so a squirt with more oil, no improvmemt, of with the bonnet after a houdini act getting at the rear hinge bolts, try it in the bonnet, it's tight, the bend on the bonnet that forms the female part of the hinge isn't round, quickly turned up a suitable brass drift, gently tap it in the hole, now nice and round and loose on the pin, assemble it all together, nice and free now.
test run of 220k and no rattle, (well the sun was shinning so I just followed it). Just out of interest I mounted a dial gauge on the bulkhead to see how much the bonnet moved when driving, that was frightening, looking at the gauge the needle flapped about as if it wasn't connected, I knew the body flexed, but there is serious movement there, hence the rattle only at certain times and luckily it was in the rattle position when I stopped.
