'It sounds like these linears are anomalous or at least unusual enough to be considered 'special places' which is interesting if Tan Hill and Milk Hill are surveying platforms as we claim. I wonder if these linears were 'sighting lines'?'
If they are surveying platforms I would imagine there was a massive map making exercise under way.
To make any map you've got to have a base line to work from. The Ordnance Survey used tide gauges to set heights above sea level. Newlyn was the starting point.http://www.ordnancesurvey.co.uk/blog/20 ... sea-level/
Once heights have been calculated meaningful calculations can be made on distances using triangulation. This would require permanent points in the landscape to work from. The best points will be at a useful height to have an unobstructed view of the surrounding landscape. In the absence of such a point it would be advantageous to create one.
It would also be useful to combine these terrestrial structures with observatories to keep an eye on celestial bodies. This would help to place the local points within a more global framework.
If this is true then there must have been a massive organisation behind the project with the finances and the skills to carry it out. Perhaps there was a society with these skills before the destructive effects of the ice ages. Once things had settled down and a period of relative stability achieved it would be essential to remap the newly modelled world.