Thanks for all your help . I've ordered some vet-bed for her which will hopefully arrive on Friday. In the meantime I hope she doesn't try and move around her cage too much. I might try a towel to see if that's better than the incontinence pad which is down just now. Only problem is that mum keeps digging it up. I could remove her (though goodness knows where, I already have two cages in the house and am running out of both cages and space!) but, seeing how much better mum did once this one was in, I'm loathe to separate them.
I've been in touch with Helping Hands and got some useful advice from her. Unfortunately, I live on a Scottish Island and there is no way I can take my wee one to a specialist.
As for what's behind it all, long story shortish:
The whole saga actually started with yet another rabbit, who was also limping, had hypothermia and then died. The PM showed a hugely inflamed cecum, but it wasn't thought to be infectious. When, a few days later, I took the remaining 4 to the vet for the Myxi jabs he pointed out that the mother had severe muscle loss on her hindquarters, but, other than that, was fine. However, her weight decreased severely over the next few days so she went in for x-rays (clear) and bloods, which showed high white blood count and low protein. She went onto antibiotics and her appetite returned. Since then (19th December) her weight has once again increased, and she's gone from being at death's door to trying to cause chaos at the surgery last week. At her weakest she was barely moving, but would stay flat on the floor. In the meantime I asked that they test for EC, which the lab did as they still had her blood sample, but it came back negative.
The third rabbit, the one I'm currently working with, showed slight symptoms about a week after the mother. However, these 'symptoms' were more that she wasn't running away from me and although I had found her in the same place in the shed every time I went in over 2 days I couldn't guarantee that she hadn't moved in the meantime. Plus, I had mentioned it to the vet who dismissed it as a concern other than to keep an eye on her, but he was confident there was no link between the three rabbits. I did take this one into the house after a couple of days when she started showing signs of hind leg paralysis, but at the time she was still a good weight and was far more 'with it' than the mother had been. She then went on to antibiotics.
I was away for a week and my partner took over care of them. His attention was mainly on the second rabbit, who ate lots during that time and improved massively. However, the third rabbit went downhill to the state she is in now, where she spends all the time lying on one side.
The whole situation has three vets stumped! Any ideas welcome.
Thanks!