The UK is literally Douglas Adams' Bureaucracy

[mharr]

So today our landlord company were formally losing their minds over a temporary rent shortfall of one tenner per week while our daughter is moving out and all the change of circumstance forms are gradually working through the system. (The account is in credit, it would take several years for this tenner to become an actual problem.)

We have spent the morning struggling to find and arrange a printed letter from another organisation that they will accept as formal proof of our address.

We are living in a building these idiots own. Their agent visited us in person when we moved in.

[Mothra]

Christ

[mharr]

I don't make a habit of tea, but that morning demanded a cuppa.

[WingSounds]

Lord of light... I have no idea how it works over there in yon sceptred isles, but if they're still being a gigantic butts, here's my suggestion.

I. Write a proof of residency. Samples can be found here, but all it really needs is your location, name, and a signature.

II. Go to your local government head/hall and get it notarised.

III. Present the signed & notarised document to your landlord's company, preferably with ID. If possible make, sure to confirm they received it; this will be helpful if, ten years in the future, they complain about said tenner again.

You're probably already past it, but I hope that helps some.
I'll put extra jasmine in the next cup, for you and yours.