The source issue is usually related to the TV or TV settings. Some TV's can be set to switch on and default to a specific HDMI source. I would look through the menus of the TV and see if any source settings can be changed.
If a maintenance reset is failing then the only option going forward is to try the full factory reset from the youview settings menu.
I have not replied earlier as I have been monitoring the performance of the box since I did the maintenance reset following your advice.
At first it was better although not all the issues were resolved, but it was tolerable. However it has been getting progressively worse and I have had to do resets on a regular basis, with more of the original issues returning.
Within the last few days it has failed to record some programmes and got stuck on channel 1. I have had to reset the box several times as it only worked briefly until the next problem occurred. These have included not pausing, not rewinding, completely freezing and not being able to play recordings etc. I have now done a software reset at least twice but the problems continue. It now seems that everytime we switch on there are problems and a reset is needed.
This is very frustrating so can you please let me know where we go from here.
Try setting it to always on then unplug and restart box then try setting it to "smart"