I watched Megafactories recently on the Bentley or Jaguar (or both!) and they 100% said Burl and being Pommy brands I took it as given.
But thinking about now the narrator was American...

This also gets me thinking about the narrator on Mythbusters whom changes pronunciations between segments let alone episodes.
Turns out he lives in Sydney (and narrates from there) was born in England and caters for US and Canadian markets!