Just get the older generation on currency.
The basic unit was the penny, called d. The d was divided into half and quarters. There were 1/4 and 1/2 d coins, the 1d, 3d and 6d. 12d was one shilling. 20s was one pound, so a pound was 240d. Before calculators all prices needed to be converted into farthings for multiplication. There was also a guinea which was 21s. Actually we still use the guinea to sell horses.
Weights were easy. 16oz to 1 pound (written lb). 14lb to one stone. So a stone is 224oz.
We use gallons too, but the imperial gallon is a bit different to the US gallon. Petrol (US=gas) is sold by the litre but we still talk of miles per gallon.
More seriously British Isles slang retains a strong regional basis - the idea of a single British slang is a non starter. We also have town/country differences and class differences. Everyone can recognise someone not from their area and not from their class. Determining the areas is more of a challenge, but often people can do it. There are still parts of the British Isles where small-area reagional accents have remained distinct - Scotland, Ireland, parts of N and W England.
