hey Blue, have you considered fitting gt bonnet locks?
Rare spares sell most of the kit, new springs,cups, srews and the machines latches themselves.
I was worried about the Capri bonnet flipping also, mine used to get a good shimmy up, even after adjusting the stoppers and it was only the dodgy latch keeping tit down.
I have seen online you can also purchase the strengthening plates that go on the catch, Burtons I think.
I bought some aerocatches to go on the escort, but are yet to fit them.