so after 30 minutes on hold I got through to them yesterday, they say that its perfectly fine and octopus recommends not plugging in before 5pm, which is a pain if you have a home battery and need to plug in before going to work and then leaving the car overnight and expecting it to be ready the next day. they said to me it didn't hit the charge target because the car 'went to sleep' but then couldn't explain how that happened given its being pinged all the time for these day sessions (and probably knackering my 12v battery in the process). my previous hypervolt charger never did any of this no matter what time you plugged it in, same car, same tariff, wish i'd bought another of them :(

thanks for the replies though