Adam,
I'd imagine the shop owners Insurance company would have something to say about this.
If that place catches fire because of that circuit, there could be a few people "in the gun".
I'd agree with Britspark, photographic evidence would be a good idea.
Oh and by the way, I reckon that this guy is some sort of a "fly-by-nighter"!. [Linked Image]
No-one in thier right mind would protect a 1.0mm cable in that manner, you might as well just hook it straight up to the main switch. [Linked Image]