Since installation last year, we have had intermittent picture zooming in and out, usually very quickly and therefore not causing much of a viewing problem. It has now gone into zoom in mode and stuck so that the edges around the picture are now gone. I'm watchiong snooker and the baulk p[ockets are now off screen. The box is a Thomson and I've tried to power off etc. Any ideas on how to return to normal as I can't find any zoom options on the remote. Thanks