Ah gotta love the trusty old EF Ghia V8....not much go's wrong but when it does...

The headlights sometimes don't work- both of them separately . If you bang the lens sometimes they will work.

Taken the globes out checked wiring and connections, all is ok Globes fit snugly into place- and no burned wires (which did happen in the old EB)

Any ideas?

If you'd said just one headlamp didn't work then I might have said it was the globe element itself if you'd been banging it. But if it's two headlamps at the same time then perhaps the headlight switch on the dashboard has a dirty contact. This is not uncommon in many cars, let alone the EF's.

Other than earths,connections.. Check the wire connections under the light relay near battery..
Also check the circuit breaker at the end of relay box..
Faulty fuses can give you issues..