Harvey is 2.35kg and a healthy weight, he was up at 2.8kg at one point and I was told he was overweight then, but every bunny is going to have a different healthy weight even if they are the same breed. I'd say if you trust your vets then they're probably right, if you don't trust them the only way to be confident is to get an opinion from another vet/vet nurse! I can't remember the exact features of a slightly overweight bunny anymore because harvey's been at his stable healthy weight for so long!