Omega Deville 18ct Gold

Afternoon All,

My father gave me his Omega watch a few months back as he has a few watches, and has just bought another Rolex so this got pushed further down the pecking order
and to be honest, its probably the only one of his watches that i'd wear. It looks a classy watch, I've only just had it adjusted to fit my wrist.
Just looking for a bit of info on it really, What year is it from? value? how to change the date?
I know the strap isn't original he purchased this 9ct gold one as he preferred it to the original that was with the watch.
any info would be greatly appreciated,



thanks