I've reported this problem but just want to check other's opinion - shouldn't "one car" be translated as "uno carro" not "un carro" which I believe translates to "a car"?
It is not a problem. "uno" drops the "o" before masculine nouns.
Sorry, that's what I meant - that "un carro" is the correct version, not "uno carro". Currently its the other way around
All I can see is "One car" and "Un coche"
The difference between "a" and "one" barely exists even in English. When you say there is "a" something, you mean there is one of it and vice versa.