As a complete aside, not electrical related at all, but quite frankly the most scary part of this whole cooker swap over.....
The original plumber who installed the hob, didn't test it, wasn't "Gas SAFE" certified and just an "odd jobs" man who does a bit of plumbing.
IT LEAKED! FOR A WEEK! Half a bottle of gas gone down into the under floor cavity of the house.... while I slept, while I played with my daughter. There are SOME benefits to still having the underfloor breather vents for the (now removed) coal fire. Even though they cause annoying drafts in winter.
I occasionally smelt gas, particularly when pulling the old oven out to inspect the wiring I had to do, but figured it was just because I'd used it recently and any "spilt" gas while lighting it, would collect in there.
I became more suspicious when, as a random impulse put my nose on the floor of the kitchen first thing in the morning when the cooker had been out of use for 12 hours. I caught a few whiffs of propane, decided to turn the bottle off and wait 15 minutes and check with my nose again. No gas smell!!!
So I pulled the oven out, turned the gas bottle on again and sprayed the gas pipe with kitchen cleaner spray. It immediately fizzed and bubbled angrily. I turned it back off. I "weighed" the bottle in my hands and swung it around, it has got liquid propane in there still, but maybe only half a bottle.
Called another plumber out. He asked why I don't get the previous guy out to fix his work. I replied, "with a gas leak, you only get one strike. I don't want him to fix it."
Looking at the joint, I seen unburnt flux, not just uncleaned flux, but unburnt flux and you could feel with your finger nail part of the joiner collar was not flowed with solder at all. Additionally there was a drop of oil dripping off the pipe (before I had used the spray). I figure this was machine oil impurity in the gas from the compressor that had been collecting over half a bottle of leaking through a tiny hole.
I did for about 5 seconds consider fixing it myself. However, I knew none of my irons stood a chance against a cooper pipe and I doubt the heat gun on max would be capable either, besides, I only have leaded solder. Anyway, the slap around the back of the head came internally rather rapidly with "IT IS GAS, NO! GET PROFESSIONAL!". Wiring, fine, careful, paranoid, planned, thought out and implemented cleanly and tested. Fine. Gas, no. Just no.