I stumbled across this thread purely by chance, I couldn't see mention of the following UK sites which are useful:-
Waterline-Ships.co.uk http://www.onboardbooks.co.uk/Wirral...logue.htm.html
Deal in new and second hand 1\1250 and 1\1200 scale ships and planes.
Ships | Antics Online
New including Neptun, cost of shipping out of UK to be taken into account.
1/1250 Scale Ships
Maintained by a collector of this scale with (other interests as well) worth browsing round as there is a lot of history to be found here.
Dockside :: Index
A UK collectors forum.
I started collecting these ships in the form of Triang Minic in the late fifties and early sixties. Then for various reasons (financial mainly) I gave up until a few years ago. Thanks to the internet and toy-fairs I was able to start again. For anyone wanting to try their hand at building from kit form Len Jordan (who doesn't have a web presence) produces 20th century merchant ships as single piece resin castings at a very low price and of a high quality, available from several of the links above.
Good hunting!