Wayne,

The only people who have decent bridleway / footpath coverage are OS, so you need to get something that has access to the OS maps, and they're not cheap.

I've been looking at MemoryMap (www.memory-map.co.uk). You can download a free copy with a demo map (the demo map is Swansea Bay!) You can get a decent amount of the UK at £130 for 1:50,000. They do 1:25,000, but they're expensive unless you want just a small amount of the UK.

By the way, if you're interested in free maps have a look at http://www.openstreetmap.org.uk - a free map created by people with GPS receivers, and http://www.npemap.org.uk/ a map made of old out-of-copyright OS maps. With a bit of effort, you can plot GPS tracks over either of these.

Paul