Dapol

[Weaver]

Dapol Model Railways in the UK mainly make N and 00 Gauge railways accesories, but they also do a range of injection-moulded plastic kits in 00 Gauge (1/76th scale) and these have many items of interest to whiffers and modellers in general (a lot of them are ex-Airfix items):

http://www.dapol.co.uk/index.php?option=com_virtuemart&page=shop.browse&category_id=25&Itemid=59

Prices are reasonable too.

Some items of note:

Wheeled excavator (dioramas: construction vehicles are hard to come by)
Stephenson's Rocket (steampunk bits)
Various cranes and crane trucks (conversions)
Scammel Scarab (so cute and 1950s you KNOW you want one  )
Modernish, intact buildings (hard to come by for dioramas)