"...(2) a double pole switch with a socket outlet mounted in the same enclosure..."
Man, you is HOT!
When I penned that bit about the switch being just a straight-thru double-pole job, I was thinking: "Dare I mention anything about those cooker switches with an integral 13A socket?", then decided to leave it be, just to see if anyone would comment, or even notice what the outcome would be if'n the feed were reversed on such a beast.
Sure enough, only you engineer boffins spotted it.
I hope you're following this to the letter, Big Ada. I hope your mate hasn't zapped himself to bits by now.
Mr. Sweeper, just to add even more fun to the pot......
45-amp double-pole shower isolator switches (minus the neon)......
See where this is going?