I am a veteran EV / PHEV owner and whilst had no issues with BP Chargmaster in ordering, having it installed or getting the app up & running. I was upgrading my old faithful Podpoint 7KW non tethered charger that had given up the ghost connecting to the App. The New Chargemaster unit However came free with my new Mercedes GLE350DE (had to pay £350 as you can't claim more than one grant) and I wanted tethered because it handily came with a 32amp cable which is crucial to achieve a full 7kw charge. So far so good and as a passive charger it works perfectly that would get it a full 5 star rating. Where it all goes horribly wrong is when you want to control the timer using the Smartcharge App to a) take advantage of off peak electricity or b) charge only to 80-90% to protect the battery if the car is not being driven the next day. As my friend Nik Hamilton discovered its near as useless resulting in either no charge or a full charge when yo don't want it. The issue appears to originate in the way the charger communicates with the app. It has a built in sim which communicates with BP rather than simply using a WiFi connection which would placecthe app & charger on the same network. The app communicates with BP and back to the charger via the sim & vice versatile. Despite my vast experience its not resulted in success in over 6 months the app says the car is connected when it's not & vice versa ot advises that is charging when it's not & vice versa. The BP help line do try their best but you can tell they are completely brow beaten & as frustrated as I am. This is a terrible shame as the charger without the app works 100% everytime with a full 7kw charge given using the 32amp cable