70s cassette sampler

It's a long shot but does anyone recall a cassette sampler, possibly given away with a magazine in the UK in the early to mid seventies (74?). All I can remember about it is one song by, I think, a European prog band with a lyric something like 'Across the valley. Demons come..' I've been trying to find that song. 
In my head it was an Island Records sampler but I have looked at all of the ones in the Archive and it is doesn't appear to be one of those. I've check through all the other various artist samplers I can find online too. 

My pleasure.