Thanks all, trying all the suggestions.
She's getting loads of probiotics, the vet prescribed "prorumen" which is basically that with minerals and vitamins. Really scratching my head as to what she could have got hold of.
Not much round here toxic. Initially thought it might have been my bay tree as there was some of the leaves in the stuff she brought up but it is definitely non-toxic. No privet, rhododendrons, yew. We do have some snowberry shrubs but only the berries are poisonous and there aren't any at the moment and a shrub at the front which i don't think they have had access to and I have no idea about.
Ivy sounds like a great idea, she loves it and might tempt her appetite, will give honey a go too.
She does seem to be picking up a bit. She got up to come over to me just for cuddles which is so like her and so nice to see again. She did show some interest in the new hay tonight. She carefully picked over it to find acceptable strands but did reject all of it but an improvement in just turing away as if I was offering rancid swill!
The silver lining is that last autumn I bought them coats as we had been predicted -15C temps that never happened and their coats have still been in their packing. Put hers on her when she was trembling and seemed to help so at least they have come in handy rather than being a complete waste of money!