Tuck shop is also the place some residential camps provide for their campers,
and staff, to buy food and drinks, and other things not available in the woods.
The best tuck shop I remember was at Camp On-da-da-waks on Golden Lake, Ontario.
Campers only had access to it during certain, restricted, days and hours. But the staff, including the junior staff (I was a counsellor-in-training that summer) could buy stuff every night after the campers were in bed, as long as you weren't on night patrol.
This tuck shop did a booming business in hamburgers and milkshakes, in addition to the usual chocolate bars and lifesavers. I'm sure the camp made almost as much from tucker as it did from fees.
Don't ask me how an Aussie term came to Canada, but this has always been the word as long as I can remember.
A memory much preferred to that of the Golden Lake Itch.