There are scams from the UK all the time.

Anyone with a bit of brain should ask why soomeone from withn the UK should hire an ESL teacher from outside with visa stuff and fees involved in a country where English is the first language. That's unless all Brits only used Manchester slang or dialect including the Queen. Since that is clearly not the case and only some highly uneducated English native speakers do, you shouldn't bother and identify it as a scam for 100 %.