That would be 'cop', used as a very informal reference to a policeman.
level crossing = railroad crossing
The American counterpart of the British word "boot" is "trunk." In the UK, "boot" refers to the storage compartment at the back of a car, while in the US, "trunk" is the term used for the same feature.
NO
The U.S. ambassador to Britain during the Civil War was Charles Francis Adams. His counterpart, the British Minister (Ambassador) to the U.S. was Richard Bickerton Pemell Lyons, the First Viscount Lyons.
Had got (British) / gotten (US)
It's the same as in US English.
No Amateur Golfer has ever won The Masters at Augusta National.
The word "cleaner" (noun, adjective) is both British and US English. The noun "cleaner" (cleaners) has the US synonym "laundry."
Bobby V's real name is Bobby Wilson.
Airplane. We speak English in the US. The British spell it 'aeroplane'.
A British billion is equal to an American billion in modern use.(Formerly, a British billion used to be equal to a US Trillion)
Colonisation or colonization is one possiblility