Having same issue with BBC i player, ITVX & Channel 4 all 4. The factory reset does work, but only until VM processes a software update. I switch my box off overnight to stop the box from being updated. And the next day have no problems and for about 2 weeks had no problems. But the other day, the box had a software update during the middle of the afternoon and then the i player etc apps stop working.
VM needs to resolve why the software updates are causing these issues. Otherwise they risk many people gradually just asking for new more up to date boxes, which presumably don't have the same compatibility issues with the software update,