hey, so sorry they aren't well again. As you prob know I have a bunny with suspected active EC too, with the incontinence problems and just general not 100% health - never finishing a moult, always snuffling/sneezing, low weight etc.
Initially she was treated with antibiotics for her incontinence a few times - in case it was a UTI. She always got better on it (which i think is because although antibiotics don't kill EC, they do interfere with it's development. So for a while she got better). We also changed her diet to low Calcium foods - so Oxbow pellets (no alfalfa in) and low calcium veg. Just in case there were tiny calcium grains in her bladder that were irritating her. The vet couldn't feel any though. her urine and blood were all tested too, with no results, no high levels of anything, no infection etc.
Then she started to get stiff back legs, until the point where she had a day where she was literally dragging her back end around.
SO the vets eventually decided it was EC. She is on a 6 week course of Panacur now (after all the great information you gave me SarahP!) and she is about 12 days into it.
She is already looking better - she seems to be trying to finish her moult (woo hoo!!!) after about 6 months! and she looks a little rounder. She eats much more rigourously, she is more confident and also her legs seem looser. I do still find the odd patch of urine in the hutch. But it does look better - she doesn't leak it while running etc.
So I just wanted to say that with the help of people on here and the process of elimination of everything else, I am positive its EC. I am worried about it coming back in the future though.