When Cliff demonstrates that he can see by walking and picking up the dime, this is taken directly from what is done by the blind forger Blythe in The Great Escape (1963).
Cliff says that the dime he "found" is a 1973-S minting. In 1973, all dimes minted in San Francisco were sold as proof sets and would lose all collectors value if removed from the proof casing.
Rebecca said she had a small tattoo removed during an outpatient procedure. However, it takes several treatments for a tattoo, of any size, to be completely removed.
When Norm and Cliff ask Robin what US television shows he watched in England, Robin mentions Sgt. Bilko, the main character of The Phil Silvers Show. In fact, The Phil Silvers Show was surprisingly popular in the UK, running nearly continuously in reruns on the BBC from the early 60s through to the 2000s. (Ironically, Bilko was known for his schemes to swindle the army, much as Norm is frequently scheming to get free beers).