Hi Ewan,
Hamish appears on the front of the Folkways LP Ding, Dong, Dollar, (1959) probably the first 'political' LP he was associated with. He was, however, 'an audience' then and didn't play or sing on the album. I remember broadcasting (illegally) from his house in Broomhill songs sung by Josh Macrae and Nigel Denver. I built the radio transmitter and we used to crash into the BBC TV about 11PM. The SNP at the time asked us not to disrupt the National Anthem!!
Cheers,
Jim