I had my chimney repaired 18 months ago,now my neighbour is trying to hold me liable for a leek in his roof which he says is caused by cracked tiles from loose bricks falling while my chimney was being repaired.this was 18 months ago and he has never mentioned it.do I have to pay?

If the chimney was damaged in the course of being "repaired", I would ask whoever repaired it to take care of it.

" trying to hold me liable " how so, has he sued you or billed you?

I would assume you used a licensed and insured contractor, unless you were on the roof, it will be up to him to prove that your workers did something that was not normal and common for that type of work.

So provide them the name and address and number of your contractor if they wish to file a claim.

In a claim like this, you don't have to prove anything, they have to prove your workers caused the damage