Father in law, an AA member wants to sign up for this.
the website asks for:
Please make sure that you have the following details to hand before you begin:
1. AA Membership / Policy No. for verification purposes
2. Email address for your PIN and e-Statement
3. Current account bank details for your direct debit
4. Vehicle registration number
In answer to the question asked, yes. All fuel purchased will be by presenting your card and providing your PIN. Your bank account then gets hit with a DD once a month.
That's the way it works for the TOPAZ card I have. If you don't have the card with you, you pay the retail price.
Also, there's a daily limit for the value of petrol you can buy. IIRC, it's EUR 100. I was caught out by that, more than once, on the rare occasions when both my car and my wife's car needed fills on the same day.