Hello,
I don't know if it's relevant, but I have been researching the history of the Barry Buddon army training ground near Dundee. I recently purchased a pull-out postcard of the camps, postmarked Edinburgh, August 1928, with a very short message beginning "Dear Mother...", signed "Reg", and addressed to Mrs C(?) Northam, Woodside Cottage, Blackmoon(?), Wellington, Somerset. If your grandfather was in the army or the territorials, might this be from him? I can send a scan of the card & message if it's of interest.
Colin