I've never tried it, but I'm told that a blown egg filled with clear bathroom sealant and left out for them can also work as a deterrant. I'm not recommending this of course since it does seem a little cruel.
The other thing though DC, if you live right near a pheasant shoot, can't you persuade the keeper to put out some Larsen traps on his side of the fence to get rid of them? You could offer to pay him a proportion of the eggs that would otherwise have been eaten!
Oh, and Mr 'Foghorn Legover' as he became known wasn't even slightly bothered by his coitus interruptus once he spied our flock of lovelies! Unfortunately the increased testosterone went to his head, and he had to go in a casserole, as it was like living with a foot high ninja all over again. However, 'Roger' the RIR is still going strong, and has sired some lovely Welsummer x RIR hens who are now laying loads of beautiful mid brown eggs. What a guy eh?