Might even be able to get this cheaper with the new user coupon, but I know that won't necessarily be guaranteed for everyone.
Use the second option 'Plug Type: 36W QC 3.0 Metal'. The first one is cheaper, but it doesn't say dual port on the image and there isn't enough info on the page. So not sure on that TBH.
Click get coupons, then select one of the £1.60 off Orders over £2.40 coupons. That should bring it down to this price. Free shipping as well.