Thanks for getting back to me.
The work was done sometime last year. As far as I know they don't have any proof except for the say so of the roofer you carried out the work.
Here is the insert from their letter to me below.
"we were involved in substantial expense in the renewal of a roof beam and renewal of the roof valley at the junction of the house at the front. The damage to our roof was caused by the totally inadequate installation, not carried out professionally, of an unnecessary down pipe and badly installed rain guttering. I think totally reasonable, request that you might contribute to the costs was that we had overpaid for the work carried out.
Alex, also, they are asking us to pay half of some new work they are looking to have done, see below.
"You have gaps where tiles have shifted and the weight of these tiles dropping to the guttering level has caused spreading damp and moss growth on the roof we had sealed a year ago and is distorting the guttering and damaging the party wall between our back bedrooms. we are having the work put in hand. As the new lead lined valley will help remove the damp on both sides our builder is asking us for half the costs and will look to you for the other half. He estimates the work to be in the region of £6,000 costs in total. This work has to be carried out to the benefit of both of us, failing this our roofer will claim the balance via the claims court, which could involve you in court expenses as well."
Am I required to pay anything to the first work they had carried out last year?
Also, am I required to pay anything towards the cost of the new work they intend to have carried out now? Also, can their roofer sue me via the courts for half of the new expense if I have not agreed to the work being carried out as per the message above.