Charming. When I was too young to drive and rode a bike I rode on the pavement. I see people riding on the pavement every day. The police certainly don't enforce it, so what's the problem with it? It's certainly safer for cyclists.
You are not very open to reasoning here are you?
As has been said, cyclists are not allowed to ride on pavements. While I do not particularly agree with this law, it is the law none the less.
With regards to Road Tax, it doesn't exist, end of story. It is essentially an emmissions tax and the last time I checked, electric vehicles and some small diesels were exempt. It would therefore be tricky to charge cyclists when there are virtually no associated emissions.
If you have a problem with cyclists slowing you down, complain to your local council and request that more cycle lanes/paths are created. Ideally, this is what cyclists actually want anyhow and as the council funds this work tax shouldn't be a concern to you.
Insurance.. I have always had my own cycle insurance covering me and others as well as my bike for theft, but untl it is law, there isn't any way to enforce it.