I have used my Curve card to pay at fuel pumps for a long time now and the authorisation the pump takes is usually £1 and that has been the case up until last week.
I have pumped fuel at both Asda and Tesco now and although the pump says it’s authorising £1, the charge on my card is £50. This is happened at multiple retailers now so this makes me think it’s a Curve issue.
It is quite normal for gas station to pre-authorise such amounts. The rules might be different between the countries and different companies. It’s also might be not the same for local and foreign cards (on the same gas station), and even type of the card (debit or credit) can make a difference.
Normally, in a few days the transaction should be fully settled and you should see either right amount on the same transaction, or full refund & new charge (also can happen).
Regarding other retailers - normally it should not happen. If it does, please double-check it with retailer and contact Curve support…
Yep I found Tesco used to do £99 pre-auth commonly. Been over a year since I’ve had to fill up now though since moving to an EV 
The Asda pump stated on the screen that it was only authorising £1, so it came as a surprise when £50 was charged to my account. I would have chalked it up to something going wrong at Asda but when it happened at Tesco too, on the same card I figured it was more a Curve issue than a retailer issue.
The ASDA pumps always seem to say £1. Our local pre-auths £10.
the same happens to me , eventhough Tesco or Asda take pre-authorization charge 1£ from other cards, when I used Curve it has taken 50£. Ive cancelled transaction and it tooks 7 days to return monies with one complaint to Curve and this transaction is still displayed as pending on Curve app. More and more problem with Curve transaction at petrol stations
Hey guys, just jumping in to say that it’s normal to receive a £50 pre-auth for pay at pump transactions. The correct amount should be adjusted after a few days.
I usually use the BP app for fuel payments even when I set £35 as default maximum and it’s what BP app shows as the amount to be reserved, Curve always first charges £50 that is later corrected to the actual amount refilled within 3 days.
But there’s still a pending £10 reserved at Sainsbury’s fuel in June even when the refilled amount of £20 has never been taken from my card. I don’t know what’s happening.
I had similar experience with non-Curve card in the past - in one case the charge was dropped long after pre-authorisation.
In another case, I noticed that gas station preauthorising different amount for the card issued locally, and for the card issued by foreign bank. There also can be a difference between debit & credit cards, class of the card, etc.
Basically, the point is that gas stations are NOT the best place to benchmark cards Their rules are very different and often weird. If you are not happy with the way particular gas station treating your card, just use another one (card or gas station ;-), as card issuer will have no control over the situation.