Oh dear 🙁 As you know, we are not qualified to give veterinary advice, since we are not vets.  Many vets will treat with Panacur on suspicion only, because E C tests are still not very reliable and can produce false negatives. I have never treated a bun with Panacur for suspected EC, but I do keep it in my rabbit first aid drawer.

I will alert the other moderators to this thread.

In my opinion, this does sound like it could be EC. Side effects of Panacur are rare, and until rather recently considered pretty much nil. There is however cases where rabbits have gone into bone marrow failure after longer term use of  fenbendazole (the active ingredient in Panacur). Some vets like to do a blood count after 20 days or so, to make sure there are enough white blood cells and platelets. This side effect is considered rare, though.

You could read up a bit on fenbendazole and weigh the pros and cons. No long ago, vets would treat with Panacur on suspicion of EC only. A normal course is 27 days, and as a rule it takes quite a long time before you see improvement.

Taking Ollie on a very long car journey to see a different vet doesn’t really seem like a very good option.

I don’t know what the dosage is, but Bam is correct on the 4 week course. This is different from what you would do if you were simply “deworming”. I have to agree with Bam that this does sound like EC. He recovered so quickly the first time, so it seemed logical to conclude it was a stroke-like event. So either he had another stroke, or he is having EC episodes. We are not vets though, so we can’t provide a diagnosis. Those are just what the most likely possibilities are.