After very extensive research (Google), I have come up with this reference from (Tony) Hancock's Half Hour from the episode "The Ladies Man":
Tony's girl is not impressed about the night out..
Muriel: It wasn't much, was it. I've had better nights.
Hancock: You've seen better days too, dear.
Hancock: Have you ever seen a biscuit tin by moonlight?
Helen: No.
Hancock: It looks rather like the Taj Mahal.
http://www.tv.com/shows/hancocks-half-hour/the-ladies-man-71643/
Do you know of Tony Hancock. He was a 'superstar' comedian in the UK in the 50's/ 60's. It makes slightly more sense in my opinon if you think of a biscuit barrel (tall with a knob on the lid) rather than flat disc-shaped tin. But only slightly.
Thanks for sharing your question. I didn't know Moz had referecned that.