As mike and Mark say, it looks to be a Scot - only from the lugs, the position of the Tecalemit fittings, and the location and type of serial number - the position of the number and the lugs used is typically as built by Rattray's in the five year period after the war. I've emailed the seller for higher resolution pictures, which may help. I'll post these to a page on the website, if he replies and forward it to the list.
Bob Reid Stonehaven Scotland
http://www.flying-scot.co.uk (mapped)