Late noticiing this I know (not suprisingly, it's now expired). Can you use these for telephone payments?
great bit of kit but amazon have it for £18 https://www.amazon.co.uk/Sum-Up-Air-Card-Reader-White/dp/B06XBDXDRM/ref=sr_1_1?ie=UTF8&qid=1515533244&sr=8-1&keywords=sumup
We've got SumUp and never had any problems. Thought the fee was higher actually, quite impressed by 1.69% - even for American Express. You can login via computer and take card payment too, although with a higher fee of 2.95% + 0.25p (no idea why a higher fee though?!)