FVP4000T - Problems with guide?

Following my previous thread, my parents are now using their new 4000T but they have run into a bit of a problem. They keep finding that when they are in the guide, if they move up or down to see what is on other channels, rather than the guide changing/moving, it's almost like ti's overlaying the new info on top of the channels that were there and you cna't read any of it. They can normally exit the guide and go back to tv but going back into the guide the overlaying is still there. The only way to get rid of it is to power it off at the wall and restart it.

Also, if they select a programme to watch, it'll change to the screen giving info about the programme and the record/watch options but often if they select watch it doesn't actually do anything just drops back to the guide and hasn't changed the channel or anything?

Has anyone else experienced issues like these?

As far as I'm aware it's on the latest software as it updated it a couple of times when I first set the thing up.