Thank you for all your help.
The food issue is that Scooby has a dodgy tum and so is on a high fibre prescriptive food from the vet which may produce the "loaf of bread" effect. I did wonder if I perhaps wasn't feeding Florence enough so upped her food a while ago but it didn't make any difference. Perhaps it's just habit now.
I will however give the pineapple a go and if this doesn't work will speak again to my vet (he was the one who recommended mushrooms and yoghurt!)
Thanks again everyone x
