Yes same to both
very concerned by the reaction to the prebiotic now though - don't want him to get gassy again
I empathise with this problem. My experience of Avipro plus with Thumper was that it was ineffective, although he had a big dysbiosis problem. (Caecum packed up completely for 10 months)
I've been reluctant to advise our mainstay, which was blackthorn leaves, because they HAVE to be gathered
after the "berries" called sloes are completely ripe - about September. They are not safely available commercially, so you would have to ask the foragers on here for help.
I don't know how blackthorn leaves actually work, but my impression is that they preferentially remove the micro organisms which make toxins which slow down the bowel. When the bowel is already slow from poor nerve supply ..... the aim is obvious.
For gas, I used a very modified "tummy rub". Never massaging directly over the abdomen, but stroking gently but firmly down the sides & slightly curving my fingers under, as Thumper would permit, when given complete freedom to move away. 1st on one side then the other.
Rather than putting direct pressure on gas filled bowel, this gently shifts the bowel from side to side in the abdomen & helps to get the gas pocket moving & disperse it. (latterly, when Thumper had exceeded the max dose of meds this was the only way I could start him up again when we had 5 mins without any bowel sounds situations)
For us, it was very close team work with vet, rabbit, & myself. I think it's probably the same for all of us, but those of us who have followed this path before you, can at least cautiously "open a few doors" - "This or that might help".
The other option for gas in this situation would be dill seed tea. 1 teaspoon of dill seeds in a mug, pour over boiling water & cool. Strain off the liquid & offer to bunny. TBH neither of mine would drink it! but I think that if we gave fresh dill leaves to Atticus it could worsen his dysbiosis considerably.