Run to the Hills (official biography), specifically states that the band worked on mixing eight tracks (from the album) in February, as they has to cut the Metal for Muthas tour short. March saw the band tour with Judas Priest, but there were no gigs between mid-April and mid-May. My guess, and it's only a guess, is that og was recorded om a separate session in April 1980.To my ears, Sanctuary sounds a lot better produced that the rest of the first album.
Was it a case that more effort was made producing it as it was to be a single, or was it possibly recorded at a different session altogether to the rest of the first album?
That's correctIt was Recorded at: Morgan Studios, London UK 1980.04.09