Suggest you get in touch with the pilot by putting his registration through
http://www.caa.co.uk/application.asp...ype=65&appid=1
As suggested before a nicely nicely approach would be best as I am sure you will appreciate. The pilot might not know that you have tried to get in touch with him even if the hotel have been difficult, so benefit of the doubt time... that said, any decent pilot will realise they have disturbed stock when they see them scattering in all directions.
That was the carrot approach.... The stick approach is to make sure he realises that regardless of whether someone follows the CAA rules of the air, insurance claims can and will happen if stock is injured in anyway. But as stressed, as soon as you get onto discussions of that nature, then any chance of a gentlemen's discussion is at an end. Use as last resort.