Americans find British accents more believable but not vice versa

Well they certainly don't trust American accents in Australia. Americans tend to be full of marketing hype and are known for doing what's profitable rather than what's right. There was a place in my home town that opened up long ago called Dave Nelson's Barbecue Spare Ribs.  Dave Nelson was a yank, or "seppo" as we call them, short for "septic tank", which is something that rhymes with "yank" and is full of shit. Dave Nelson made the mistake of being in his own TV ads, telling us to come to his restaurant.  For a start, Australians don't want to be told anything by a American. Also, back then ribs were a part of the animal that you threw in the trash, much like chicken wings, so all we thought was "a yank profiting from trash". His restaurant didn't do well, so he had to drop the TV ads and change the name of his restaurant to "Aussie Ribs". He's still around but now runs a Mexican restaurant called Cisco's. They still serve barbecued spare ribs.