In reply to BattyMilk:
As other posters say, the Postion Format is BNG. (British National Grid). Also, the Map Datum is Ord Survey GB, and the Map Spheroid is Airy. These are the three compatible settings.
Typically if you are in the Alps. Position format is UTM UPS, Map Datum is WGS 84, and Map Spheroid is WGS 84.
This helps with the newer GPS friendly maps, in all the Alpine countries. Universal Transverse Mercator (Universal Positioning System) has simplified all the individual French, Swiss, Italian, Austrian etc variations, and there are many. Much easier to work with than Lat/Long. This should keep you on the right track or route or path. Don't forget to set your Activity to direct routing.