@AlexPeekay -- is that a recessed area in an outside wall? Is it a south-side wall, that is getting more solar-heating than it was getting during the September-to-March "winter" in Victoria? Is the ambient room-temperature now warmer?
Have you tried fully-disconnecting all the cables from the Shaw box, then taking a can of a compressed air, and blowing-out any dust that might have accumulated inside the box? The dust could be acting as a "blanket" that is keeping the electronic components warmer.
@ziggurcat -- I can adjust the volume, but I cannot get into the guide or settings right now.
I presume that you have synchronized your Shaw remote-control to your specific TV.
Thus, some buttons on your remote: on/off, volume up/down, mute, source send signals directly to the TV,
while some buttons: guide, play/pause, rewind, channel up/down, settings are sent to the (non-responsive?) Shaw TV box.
So, your description makes perfect sense.
The signal had returned at that point, so the guide/settings buttons should have been responding. I had to unplug/plug the unit back in to get it to work again.