[The Dwarfs' cottage was built for the 1938 Ideal Home Exhibition (an annual show sponsored by the Daily Mail newspaper, and held at Olympia in April). Although not featured in the illustration, it is listed as one of the exhibits on this advertisement: http://www.fulltable.com/vts/e/exhib/c.jpg
Here is a review of the exhibition (from The Catholic Herald). The cottage is mentioned, but the reviewer, lacking a young person in tow, was too embarrassed to go in!
Finally, a quote from Annette Kuhn's academic paper "Snow White in 1930s Britain":
"Among the promotional ideas set out in a UK press book for the film is a short article on the dwarfs’ house and the expertise behind its creation. Alongside pictures of items of furniture from the house is proffered the suggestion that ‘practically everything in this fantastic but charming abode could be easily adapted to a modern country home or mountain lodge’. This rather far-fetched notion may indicate the depth of misunderstanding in Burbank, California, of daily life in Britain in the late 1930s, when not all Britons were strangers to aspirations of domestic perfection. At a time when hundreds of thousands of new houses were being built on the fringes of Britain’s cities, dreams–especially among lower-middle-class women–of the desirable (albeit suburban-modern rather than rustic) home found expression in the annual Daily Mail Ideal Home Exhibition in London [Ryan 1995]. It is perhaps not surprising, therefore, that the 1938 exhibition featured a replica of the dwarfs’ house, its scale suggesting that it was made for small people–dwarfs and children. This suggests something of how Disney’s film and its promotion, at a time when consumerism had barely begun to emerge in Britain, keyed into popular, and perhaps profound, imaginings of ‘home’ and ‘homeyness’ to sell a dream of possessing things–tableware, ornaments, and the like–and above all an ordered and beautiful home. And indeed there is contemporary evidence to suggest that Snow White’s domestic topos and its homemaking scenes made a considerable impression at the time on audiences of all ages, an impression at least as marked as that made by the film’s vividly recollected ‘frightening’ passages."]