Sutton Coldfield Freeview changing channels

Yesterday and this morning I was watching the TV through my Humax box when it suddenly switched to BBC 1 "odd" I thought and changed it back only for it to switch again. Change over and bam. Couldn't stick to that channel at all.

Looking more closely it seems to be that any channels in Mux A (BBC1, 2, BBC3, BBC4 Parliament, News, CBBC) are defaulting to BBC1 after a while. The tell-tale is that once on BBC1 "Please Wait" flashes up top right where the Red Button stuff is.

With Sutton Coldfield getting ready to switch over fully to digital I'm guessing that it's the sub-channel causing this. It's quite possible as if you selected the Red Button and picked Multi-screen News or some such it takes you to channel 301, 302 whatever so it's quite possible for it to receive a signal telling it to switch channels.

Now as I say this only seems to be happening to Mux A and oddly only seems to be happening with the Humax box; the integrated tuner in my TV seems fine. I'm guessing that the Humax is perhaps a little more sensitive or susceptible to this change.