"Apparently AOPA teach and examine in PPL theory see abstract below from their site but they are not, as far as I know an ATO"
Hello,
I teach the PPL Ground School course at AOPA. You are correct that AOPA is not an ATO. I work with Flyers Flying School at Elstree, an approved ATO, and the AOPA classroom in Victoria is a registered and CAA approved classroom and examination centre.
It is AOPA, we'd not have got that wrong!
Adam Winter
Our new course starts on March 9th at AOPA in Victoria London