Hi, Thanks for your answer. 
Just a quick info I never tried yet the strava heatmap so this is interesting. But still I didnt mean that this should be the reference, but should be taken into account rather. In some case it might be ok in others no. 
So in this specific area I find (-3.73, -1.83) with esri clarified and (1.13, -3.39) with Bing.  And if I use buildings it is (2.38, -1.68) with Bing and (-5.12, -2.96) with ESri clarified. I reckon the buildings are not clean in this area.  So we still have a 3m diff. I would agree to take (1.13, -3.39) with Bing. Also I think generally Bing is more up to date than Esri. (i know because of some new buildings appear on Bing and not Esri). Would you agree?