Morning Dennis,
No personal voice message on that number just the standard service provider one, was hoping for a call back to get a pic for the “believers” but the mystery goes on, as you know I’m with you on this as both Trev H and a local lad who worked at Guy Motors have said that none was ever built.
The advert may have been a typo though and should have read, " Ex Smith’s of Milnthorpe"? Got one of my lads up round Sellafield and Millom today so if I do get a call back he will be heading there for a photo shoot, Cheer’s Pete