Weirdly, I have been. Taken it up, obvs. Now, I am on LPG, not mains gas, but even so. Our bill got reduced by £50.00 pm a few months ago, based on usage, apparently. I spoke to them the other day as the contract was up for renewal. Was dreading it. But they said I could fix at the same DD and unit price for 12 months, "to see how it plays out", then look at a variable after that.
Its about the first time I have been glad we are on LPG in 22 years.
Whether they have a ton of stored LPG bought at pre crap prices, or LPG is uncorrelated to mains gas I dont know.