The LA's have maps that will confirm TRO's. I do not have to check TRO's for road riding as I do not use pavements. I do however check when taking groups out MTB'ing. OS maps provide enough detail to tell is a trail is classed as a road, bridleway, shared access, etc. This is how I was taught to do it. I was also taught if in doubt don't. What do you not understand?
I love the way you change the subject to avoid the difficult answers. We were talking about cycling on pavements alongside the road, not on bridleways or byways or white roads. So how does the person that would like to use pavements find out?
I think you will find the LA TRO maps are all about Parking and Waiting restrictions and there are no maps of shared use pavement TROs (although I wouldn't rule out the odd one existing as an exception). Someone has tried to do it for Cambridge. Help yourself to wading through it if you want to find out what might and might not be legal to cycle on.
So lets get back to the question. If you want to cycle from A to B and you don't want to cycle on the road how are you expected to know the legality of cycling on the pavement and how are the police expected to know?