Interesting. It says "Payment may be made in Sterling notes".

The use of the word "notes" seems to specifically exclude coins, so does this mean that no change was given and you had to make an overpayment even if you had the exact amount? Or accept some fruit juices (15p) as change.

In 1981 pound notes were still in use so it wouldn't be that bad. (The Isle of Man 50p which qualifies as Sterling was still in use too.)

Also travellers cheques. I have never seen or used them - did they come in amounts small enough to be usable for these BOB items?