Thanks. I've pu this up on osm.wiki/OpenStreetMap_in_the_media#November_2011 .

Rhubarb - I showed my wife the default map that came with the Garmin unit and she was not impressed (i.e. just provides the large highways, not residential roads). Therefore, I think I will be uploading OSM maps to the unit in the near future to satisfy her expectations in this area :-)

Consider the interesting Excel function related at http://www.gps-practice-and-fun.com/gps-coordinates.html . Do you think that increasing the accuracy of the four measured points by multiple measurements would have significantly enhanced the end result extrapolated position of the '3rd steeple' in the example? What about replacing two of the four points with distance measures, such as one might do if one wanted to accurately place multiple objects in a relatively small area (e.g. sculpture garden, cemetery, accident site)? Distances could be measured using either a laser ranging instrument or a rolling linear measure.