i also use sum up ..had it for over a year now...you can take payment over the phone too with the virtual terminal on the app,,,,i use mine every week for contactless payments but its only a few here and there...
i reckon 70% of my customers pay by BACS now since the lockdown ,10% card and 20% cash payments on day of clean,thats it....occasionally i get the odd cheque too but only had one £45 cheque in 3 months!