This may be more of a post to vent, as I'm 3 months pregnant and worried about how much this is going to stress out little pip. It's a slightly long-winded story but I'll try to keep to the basics.
We're in a ground floor flat and share a party wall with our neighbour who has damp issues on her side of the wall (both rooms are bathrooms). Her bathroom and four other areas in her flat have been damp proofed and restored but in October she sent one of the damp guys to look at our bathroom as the plaster wasn't drying properly; during this inspection the surveyor took a quick peek under our bath and said we had leaking pipe. Later we pulled everything out and discovered that water was actually getting through the mastic around the bath. We immediately stopped using the shower and bath, had the mastic replaced professionally and dried everything out with a dehumidifier. We also then had a plumber check all the bathroom piping for actual leaks, but there were none.
Since the damp guy came round, our neighbour started blaming us for her damp, despite the fact that four other unrelated areas in her flat have also had to be damp proofed. Our building is from around 1850, so it's not unusual to have damp problems, though we have none ourselves but do get condensation on the windows from time to time. After we sorted everything, the neighbour's plaster still wasn't drying out, so the damp company refused to return to check for other issues and told her we must have a different leak (hence us paying for a plumber to confirm otherwise). We asked her to keep us updated and to let us know if there was anything else she wanted us to do.
Anyway, today after two months of silence, she posted a new report from the damp company under our door; they now say the initial bathroom damp was caused by a leak from our flat, and the neighbour is heavily suggesting that we pay for all the damp proofing and repair to her home and sending loosely veiled threats about getting lawyers involved. Now, I'm not saying that our leak had no effect on her bathroom wall; I don't know if a leak can cause actual damp (wouldn't it be water damage?) but it wouldn't have helped regardless. We feel incredibly sorry for her situation and are happy to offer to pay for the bathroom wall, but I don't think it's fair for her to ask us to pay for the damp proofing throughout her home as she clearly has a general damp issue.
We're planning to offer to pay a portion of the costs but I don't know what her reaction is going to be and I'm afraid she's going to get lawyers involved anyway. I really don't want to be in a dispute as I've already lived through neighbour hell before (or a very different sort) and we own this place. What should we do next?