I noticed it mentioned OS maps somewhere on the site - does that mean actual 1:50/25,000 OS maps?
There is a sort of OS map on the app which is called Streetview but it certainly isn't 50 or 25,000. There are no footpaths or rights of way marked on it so if that's your sort of caching then it's not that special.
What I have found is downloading the offline maps for England gives you footpaths and tracks. I can't vouch for their accuracy as I haven't tried it out yet and as far as I can see there's no legend showing rights of way or not. Hope this helps.