When I am in `Mountain Leader Mode' I use OS map and compass. The large scale of an OS map plus some skill makes it easy to determine one's position, even on a blank hillside, with a high degree of accuracy. The map and compass then makes it easy to navigate with the same accuracy. In practice there ar very few times when the compass is needed here as with good mapping navigation by map features alone is sufficient.I consider that GPS for this application is often just means for people who don't know what they are doing to get themselves into trouble.
On a bike or in a car its different. Then I use GPS. The greater distances covered requires lower scale maps which do not have the detail for an accurate position fix, unless you are in a desert riding a compass bearing is not an option, even with quality `adjustable' compasses accuracy is compromised by sitting on a big lump of steel.
I have used a Garmin 12 GPS in my car (before routing GPS) Altough some of its features were of use on rare occasions, the compass was not one of them.
