Just catching up – to add a bit about Flarm.
It would not be necessary to install Flarm on fixed obstacles. It has the capability of a database of obstacles which give alerts to an airborne unit, which has the database stored, when getting too close.
Flarm is used on the continent – certainly in Switzerland and I think in other Alpine areas – by helicopters among others, for obstacle warnings. I think the database started with cables close to mountains and crossing valleys that were hazards, and there had been too many fatal accidents. When Flarm was developed for gliders, the heli and other operators realised its benefits and also adopted it, so it is now (almost?) universal in those areas. The technology is available here and now. A UK obstacle database would need to be developed, but it could be done, at a cost – or even by an individual or operation for an area important to him/her/them.
If anyone is seriously interested, I suggest looking at the Flarm website for information.
Flarm - Homepage :
“shows nearby traffic, warns visually and acoustically of approaching other aircraft or fixed obstacles
“embedded database covers Italian, Swiss, Austrian, French and German obstacles, with updates (functionality at cost)”
Maybe the Flarm people would post something on here.