Hi Vivien
Here is a group i found to be very helpfull with my bunny problems and illnesses.
U can join them write to them and u get responds from other group members pretty fast. I would write to them about bit bit and see what feed back you get. From time to time i write to them about my bunnies and it has always been helpfull even during the times the vets could not do anything. Its worth a try as i know u love bit bit very much. Take care and hugs to bit bit...
Here is the link:
http://www.bio.miami.edu/hare/etherbun.html