Follow up on this. Spent over an hour/dropped call on the phone yesterday with a very helpful/pleasant young man. He went through everything, phone type/settings etc. As it's a business account we'd been receiving emails that the authenticator app will be essential to continue being able to use them online. So, it transpires it's not needed at all!!! Cos it's a "small" business account, as in, no millions in it....gahhh. After all that.
