it's the OP's cock-up. fit the wireless switch at no cost to customer, after admitting he screwed up.
That's what i mean tel, its the OP's cock up ... i for one wouldn't want fancy dance wireless switches with remotes that would get lost (i literally lose the TV remote in my gaff on average every 10minutes lol)
The OP fk'd up with the design, he needs to install it properly then either have his indemnity insurance pay for the plasterer to come back and re-do what he's done, or front the bill himself.