Welcome.

There would be a big difference in value between a 2448 and a 2456 - a 2448 is gold plate, a 2456 18K gold. The watch pictured looks to be a 2448, there seem to be signs of wear on the plate but it's hard to tell from a single photo.

It does look to be correct though, from what can be seen from that photo. I'd put a 2448 between £1500 and £1750, more for a really good one or from a dealer. 2456s come up much more rarely - you'd be looking at between £4 and £6000 for one of those.