In reply to stewieb:
> Are they detailed enough for walking routes etc?
OS 1:25000 has too much (irrelevant) detail, 1:50000 too little.
Harvey maps 1:40000 are excellent for relevant detail (eg walls, fences, types of land, wood and forest, and prominent boulders and cairns). Only downside is getting used to the scale and learning your 15 and 75 times tables for countours.