For what it is worth I have a 10" record released by Mike, John and Sandy from around about 1964 pressed through the Craighall pressing plant. Most songs are credited as either trad or attributed to John Croall with the exception of a Woody Guthrie cover. The record is titled 'at Moby Dick's' which I have always assumed was a pub or hostelry in Edinburgh around that time. I also have another 45 also pressed at Craighall on the Lothian label with four tracks by John Croall (which one I am not sure) from around 1965 so similar vintage to the Polydor single (which I also own). I've been trying to learn whether or not a Steve Croall who released 2 45s in Sweden in the late 1960s was related in anyway as he was Scottish as far as I can make out. Seem to have been quite a few Croalls around the folk scene at the time