This is a wonderful post as always @pandapoef. I'm gonna try a number of these. As I live in the countryside we regularly get inundated with flies over the summer months (almost as much as we get with Midges).
I'll let you know how succcessful I am. Thank you again.
Thank you for your kinds words @alioops ! I'm already excited to hear about your experiences with some of these methods, I wish you the best of luck and may you never get troubled with flies again! ^^