Rummages around on the shelf of things that may be useful one day...
Simpkins tins of boiled sweets from the local pound-shop are 3.8" in diameter by 1.5" deep, Lidl or Aldi (I always get them confused) also stock a similar size tin of confectionery.
The enamel storage bowls aka tiffin-tins are also starting to reappear in £shops but these have a maximum diameter of 4.3" and are 2.2" deep
Sarah-Beth tea comes in tins 3.5" square by 4.6" tall