Ugh! It was a Not Good To Fly warning but I chose to ignore it as the wind was only 20mph and the sun was out blue skies. Should have looked at it at 100ft up. Anyway all good, took off from a wide open nearby park (the Downs in Bristol UK) went up to 100ft and the wind started to take it and then I experienced ATTI. Didn’t panic (unusual for me as I have lost and recovered this Spark twice already) and walked to where I thought I might see it. No sign but could hear it and bless it, RTH kicked in and the sound got louder. Back came the connection and I allowed it to land precisely where it took off from. Lesson learnt, take proper note of conditions, although I think I have flown in similar strength winds before, and have faith in RTH.