I have reached the stage were I want my girl to stop via whistle as I'm sending her away from me. She is good on stopping when coming towards me but I would love some advice on how to train her to stop when her back is to me as I don't want to make any unavoidable mistakes. Love Sonja

Hi Sonja. You should be able to stop her with the same signal regardless of her direction.  I  simply use one long blow for my dogs to stop immediately what they are doing and look at me for a hand signal. 

Teach her a whistle signal that signifies stop what you are doing immediately and give me your attention, once you have got her attention use whatever hand signal in use for a down and give a blast on the whistle. These blasts must differ from any other whistle signal you use. Once she has mastered the stop and recogognises the combination of hand a whistle blast you can then leave out the hand signal and use the double blast  combination.  What you are teaching her will be an immediate stop, and drop into down stay position.

Reading that back makes very little sense, it works for me but have difficulty in explaning :D

Thanks Kayc, it makes perfect sense, thanks for your advice. Many thanks Sonja