I think it's later than the 1972 match basing it on the crowd shown. That match had a gate of under 5,000, and looking at the stand, it looks as though the numbers would have been in the region of double that figure.
Thanks so much for that! My grandad, uncle, dad and I are all on that picture - only me and my dad left now.
It's definitely the 1971/72 match. That's Frank Sharp taking the throw in, with David Booth stood next to him.