Looking at the bill,
They've corrected an over estimate on the old meter resulting in a minus usage and credit
It was misleading seeing 2 readings / charges on the new meter at first but it's 2 consecutive periods not 2 rates.
So although it's 2 rate meter they are only making one charge, presumably the meter is either configured as a single rate meter or they are amalgamating the Day and Night usage readings.
The latter is unlikely as they would show the Day and Night readings.
The second, previously Off peak consumer unit connected to cable LLL at the meter, may or may not be on, it depends how they configured the meter.
Does it need to be on, do you have Storage heaters or anything else connected to it?
First usage on the new meter = 0 actual to estimated 77.. 24/09 to 01/10/21
Second usage on the new = 77 estimated to 553 actual..01/10 to 13/11/21
It looks like between the 2 billing periods above there has been a rate increase, as your current tariff is variable as stated in the communication from them, 17.93p/kw to 19.78p/kwh, probably due current energy costs.
And there also looks to have been a small rate increase at the time the meter was replaced from 17.86p/kwh to 17.93p/kwh