Rads, out of interest how much do you feed? I used to give Sweep 2 tablespoons of food, but found he ate hardly any of it and stashed so much I have no idea how he had room for him
I reduced this to 1 tablespoon plus the extra bits which I found I was feeding more often, but he actually ate it rather than stashed the entire lot. Of course I made sure he wasn't loosing a lot of weight, and he seemed happier with a smaller amount of food more often, rather than a large amount less often. I also would give him folded up cardboard tube parcels with his food in once a week or so to make him REALLY work for it, which he loved and he'd sit and eat it (rather than stash it) once he'd got into the package! I found we were wasting a lot less by giving less food more often.
Do you scatter feed or bowl feed? Can't remember!
ETA - I just wanted to add that Sweep did stash food too, but it was a lot less and he actually ate the stash!
You could also try the tough love method, of not giving her any more until she's eaten what she has maybe? It's hard at first but they quickly learn!