Coins with Germanic rather than Latin origin were the Mark, 13/4 (thirteen shillings and fourpence), two thirds of a pound, and the groat (6/8, half a Mark). Try doing that in decimal. Is there a coin that represents three point three recurring pennies?

In armed forces slang, five-pound notes are "divvies", standing for "drinks vouchers". BDV (blue drinks voucher) was also used. Fivers were sometimes also "blueys" before the insipid turquoise version with Elizabeth Fry on one side, and ten-pound notes still are "brownies".