Erstwhile vintage maps and charts at Achica
Interestingly, we featured an Erstwhile map at the end of 2013. The downside being that it was only available in Australia (unless you happen to live in Australia, obviously). However, we've just noticed the Erstwhile vintage maps and charts at Achica, which means they are available in the UK - and discounted.
Plenty to choose from, but we've picked two contrasting versions of the same thing. Above is a 1968 wall map called Physical Map of the British Isles, published by Chas. H. Scally & Co. and below is the 1930s Great Britain, her natural and industrial resources map, which was published in New York and distributed by the British Information Service.
Both of those are currently discounted to £135. See the Achica site for everything on offer.