I think I'd remove the child from the creche too. Maybe its the environment, or other children there....thats causing your child to bite....if he is bored, copying another child, or not getting any attention from the child carers...I can understand why something like this would happen. Moreover, strapping him in his buggy, IS child abuse and that's the reason I would move the child....because it would make me think what else does the creche deem acceptable if they can do that to a child?
Good luck with finding a good creche!