Skimming through a couple of magazines offers the following:
Staples & Vine
www.staplesandvine.com
Thomas Gunn Miniatures:
www.tomgunn.co.uk
These seem to supply ready built models to larger scales, which I suspect is what you're after. I've not dealt with either company, as I'm a 1/72nd scale stick-the-bits-and slap-n-paint builder.
Hope this helps a bit