HeymSR20-
I was in London a couple of years ago and I visited H&H and Purdey.
The guns I saw were not nice. I would rather buy a pre-WW1 H&H, Purdey, or Boss and then have it restocked to fit me.
You could afford to have it completely redone/restocked and re-bbled by the maker for less than the cost of a new gun.
It would be a nicer gun, too.
I have seen a few new W.W. Greener SxSs. Beautiful guns. If you can order one of those, do it. I'm not sure if they're taking any more orders, though.
William Larkin More has a new W.W. Greener 16g that is beautiful. I would buy that one before I would go with anything new from London.
What kind of gun are you looking for, anyway? O/U? SxS?
OWD