In case you didn’t hear/see it, there was a suggestion which came from a BBC email that everyone should take readings from the gas and electricity meters today and submit to their supplier.
This should ensure you should pay today’s rates for gas/electricity used up to the end of today rather than paying 1st October prices for last month’s usage.

Hope that makes sense!

I took photos of my smart meter readings so am not quite sure how it works with those.  Does one ever get estimated readings with these?