https://cycle.travel/advice/canal_cycling has some info and cautions.
If you're intending to use the Trent and Mersey Canal, Coventry, Birmingham and Fazeley and Grand Union Canals, be aware the towpath is almost unrideable rough in some places and missing in others, including tunnels, so you'll need to use roads for those.
Stopping a bit short of Camden Lock may also be a good idea, as cycling is banned at the lock itself, last time I tried.
Good luck!