So.

Well, the vet came to see Bonnie today.

And basically, she has confirmed our suspicions that the problem is likely to be in her hocks. So Bonnie will be going for a trip to the vets on Monday so they can do a full lameness assessment, nerve blocks etc. Then at least I'll know for definite what the problem is and what further action may need to be taken.

It seems like she might even have to have the same treatment as Mayfly had. Like Annabel said, they really are as bad as each other. :)

I just hope that this can all get sorted out, and I can have a happy comfortable Bonnie!