I decided to pay my initial £100 deposit using Apple Pay. I selected my Barclays Debit card, and payment failed the first time. So I tried it a second time and it went through ok.
2 minutes later I got a text message from Barclays to ask me to confirm the transaction (along with another Apple pay transaction I’d done the same day.) I confirmed it.
On checking today, the £100 deposit has come out of a completely different card! (My Nationwide debit card.) The other transaction went correctly from my Barclays debit card.
This surely is a fundamental error that needs addressing urgently. Fortunately I had funds in my Nationwide account but if I hadn’t could now be facing bank charges. The fact that I have a text from Barclays is proof I didn’t make a mistake when paying.