1970s Omega Deville 18ct Solid Gold Self Winding

Good evening Omega Family.

I recently received one of my late Grandfathers beautiful pieces.

It's 18kt solid gold, with the 750 kt marking on the clasp. It's nice solid piece in lovely condition. Self winding in perfect working order.

Far too small for my wrist.

I'm wondering if anyone might know the exact model or year? Or where i could find this out?

I'm in South Australia.