Help me find a solution for an extra tall letterbox hole

[MandarinOrange]

We bought a fixer-upper Edwardian house and are slowly making it weatherproof and liveable.

The letterbox currently has no draught excluder or plate, so the wind whistles through. However I can't find one that fits, because the hole is too tall at 80mm. Usually letterbox holes have a height of 40-46mm. The width of 250mm is fine. Can any of you expert mumsnetters find a suitable draught excluder where I have failed? To further complicate matters, it is a vertical rather than a horizontal letterbox, so a closing mechanism that depends on gravity is also not suitable. The bolts are 270mm apart.

Or an alternative solution I saw on a website was to reduce the size of the interior door hole using wedges or slats (usually made of wood or plastic). Any suggestions for where I could buy wedges or slats? Or how-to guides to help me through this?

Thanks very much for any help you can provide

Oh my gosh. I think that might do the trick. I'm going to draw the dimensions onto a piece of paper and see how it would fit. Thank you so much.

In fact thank you very much to everyone who has replied. I never expected so many suggestions. It is very much appreciated.

Here’s a photo of the aperture from the hall. You can see the hinge of the letterbox opening

And here’s the letterbox viewed from outside

I am going to order the 'draught proof inner tidy' that wonkylegs suggested, in applied bronze. I cut it a mock-up of paper and it looks like it will fit. The bolts at top and bottom are slightly further apart than the aperture, but they look like they can be filed so that it fits.

Hurrah! No more whistling arctic wind through the letterbox (hopefully). Also no more viewing all the paint splodges of the previous owner.

Thank you again

So here it is - the new letterbox tidy from InBrass all the way from Edinburgh.
Looks great, makes the letterbox more secure and best of all, keeps the cold air out.
Thanks so much for your help. I honestly thought we were heading towards filling it in and making a new letterbox hole. Really appreciate it.

Looks fab. Glad you got it sorted.