What condition was the wall in before this incident and before the tree
roots started to damage it? It appears that it was fine.
If that is the case, they are liable for the whole cost of the wall.
The situation would be different if the wall (tree roots apart) was in poor
condition before the tree damaged it.
In the wall is built to a better state than it was before the roots (it
didn't need any attention) then they cannot claim any betterment.
If the wall had been falling down already and the tree roots and the tree
falling simply helped it on its way they would only be responsible for a small
proportion of the cost.
There is a claim for loss of amenity in the garden but it is not worth a
lot of money, probably a few hundred pounds.
However your son is also under a duty to mitigate his loss by dealing with
this himself and it is unlikely therefore that he could claim the loss of use
for two years. It has not helped his claim for loss of use, the fact that he
has been waiting for the other side to do it rather than taking a proactive
role in doing it himself and then suing them.
Can I help further?
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