Having said that I understand very well how dreadful disputes with neighbours are, and hope sincerely that yours is resolved as well as possible.
I don't think cat disputes (or lost cats in general) about garages or houses or other buildings tend to work out particularly well. One person I knew who worked for a well known pet charity complained of the what they regarded as (too) high failure rates based on incorrect and erroneous information and panicking. On the other hand these places end up with a lot of deliberately abandoned pets or ones that are presumed to simply be lost.
We had a cat die on our road through being locked in a neighbour's garage. Unfortunately sometimes a lost cat brings out the worst in people because I saw these neighbours going round pestering all the neighbours they didn't get on with convinced that as they didn't get on with them that the neighbour wouldn't bother searching properly etc and exaggerating the ease of being able to get hold of people. Unfortunately the cat turned up a couple of month's later in a 'good' neighbour's garage 5 doors away
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