The Four Steps to using a compass, from the Ordnance Survey’s #GetOutside Guide.
The fast settling needle Moscow 3C compass can be purchased here.
Different types of Silva compass, with their various pros and cons can be found here.
The amazingly robust, super waterproof Mourne Mountains Map from Harveys, the Superwalker XT25 can be found here.
The technique of aiming off is explained here.
This article covers aiming off, as well as handrails and attack points.