The big question here is; Does the switch have a neutral (and for that matter, an earth connection as well)?
In a switch, blue or black wires do not necessarily mean neutral.
Are there some wires connected up in a separate connector block tucked away behind the switch faceplate?
You could possibly get the power from a socket circuit, via a fused spur unit, which would usually need something like a 3 or 5 amp fuse fitted.