Thanks guys.
I have the parts from a Mk2 and they won't fit as the Mk2 pin in metric and larger in diameter, and the catch opens towards the front of the vehicle by lifting a tab whereas the Mk1 catch opens left to right by simply sliding it. As a result, the captive nuts in the Mk1 bonnet that hold the catch are at right angles to what the Mk2 require.
Simon, thanks for the assist, but with time pressing, and Chris having all the parts I need, I'm going to have to go with him.
Unless things go pear shape, this may be the end of my search.
Thanks again to all.
Paul.