@M+Facey I think it's a software issue. Others, myself included, have had the same issue where the screen goes black but the sound continues.
A factory reset seems to resolve this for a period (I had it two weeks ago, did a factory reset as advised by the advisor I was speaking to and it didn't happen again until today after the latest update was received) but you should speak to Sky before doing this as it can cause further problems. There is a thought that after receiving the update you need to clear the TV cache by doing a hard reset. Only time will tell though as to whether that hard reset I've done today resolved it.
I doubt it's a faulty TV myself but speaking to Sky directly would give you a better idea.
