We're about to move out of the property we are currently renting, and unfortunately my 2 year old did some damage to the office walls. It's wallpapered and then painted, and none of the damage goes past the wallpaper. The paint job is at least 20 years old, impossible to say how old the underlying wallpaper is. It's an obvious diy that was not done very well. What can the landlord legally charge us for? I know it can be rectified with some polyfilla and a can of paint. Does the standard calculate the cost of the job, divide by useful life left, and then that's what we owe apply to walls? The landlord can't try to claim the cost of hiring a pro to paint when it was a diy job to begin with can they? I am aware they will be able to charge for their own time, so long as it's reasonable, I don't expect anyone to work for free.
If it is done by the useful life, how long does pain/wallpapert typically last? I'm from the US so I only know how long things in the US are considered to last (and I'm especially unfamiliar with wallpaper).