cat has started spraying me?

at easter my son moved back home, he brought his 2 cats toby and tyler brothers i allready had 7 cats, we did all the introductions properly and all went well, toby and tyler were indoor cats only because of where they lived next to a road, i live in the country so they were allowed out, and they love it outside in the garden and fields, toby was a very timid cat at his old house, well hes really come out of his shell here, we have the odd scuffle with one of my cats but thats getting better, a few days ago toby started spraying in the room, well last night i was in the garden watching the hedgehogs, have thier evening walk through and toby sprayed my leg, then i went to the loo in the middle of the night and he sprayed me again. while i was sat on the loo. urrrrr i have been useing feliway since they arrived, there is nothing wrong medically with any of the cats, im wondering if anyone has any suggestions, none of my cats have ever sprayed in the house, toby has never sprayed up till now in either of his homes, all the cats have been fixed,