Paul,
Getting her screaming with excitement for a toy will help, just do a couple of highly motivated retreives and then put her away, don't worry about clinical retrieves to hand, just get her wildly excited about the "game". Having the dog on a lead and throwing a toy for a older dog will make her jealous and increase her drive If she still shows nodesire to play you could always make it a compulsive retrieve?
I have a shepherd here who used to eat the rabbits he caught, just stopped it one day My terrier is the same, the first few rats on a trip may be eaten before they settle do