Unusually large gas bill !!!!

D_M_E

In my case, when I moved into my current property the previous owner - electricity in this case - used an average of 25KwH per day and EoN tried billing me for estimated use based on that, despite me sending photos of actual readings and my own average readings of 3KwH per day.

They took some convincing and some time to accept I wasn't as profligate as the previous occupier.

In your daughter's case if she has had no gas being used by a boiler then the only useage would be for cooking - if she uses a gas cooker - and that usage would or should be very low and therefore anything more than about 5KwH gas daily usage (and that's being generous for a bit of gas hob cooking) should be strongly disputed.

Don't forget to allow for the daily standing charge as part of the bill.