I had one return months after it being released I am not sure how long. It was captured by a soldier at a kit flying exhibition and returned to me by way of the band on it's leg. I had two return to me just a few days ago after a release they were not prepared for 3 days after the fact (that turned out to be my own stupidity.). Really your guess as as good as anybodies in this case. Do you think your loft location could be part of the problem? Poor visibility from your house and surrounding roof tops?I am wondering the chances they will return.