Party wall damp / flashing problem - who pays?

[samyell]

Hi All,
Just wonder if anyone can offer me a bit of advice. We live in a 1890 mid terrace house and have had a small damp problem in a first floor bedroom. The wall where the damp patch has come through is on a party (our next door neighbours bedroom is on the other side). Our neighbour told me that they have a small damp patch in the same place in their bedroom and came round to ask me if we could take a look on the roof to see if we could find the problem on either side of the wall.
I climbed the ladder and can see no cracks or any where that water could be getting in on our side. The coping stones where replaced about 15 years ago and the flashing was re-done on our side at the same time. However when I looked on the neighbours side of the party wall I can see that the flashing has been really badly fitted (pushed up face of wall and then skimmed over - not chased into the mortar or set under the coping stones) and all the render has cracked off and left big gaps behind the flashing where water can get in.
Im not sure who is responsible for paying for / commissioning the necessary work to remedy the problem. We get on very well with our neighbours and I don't want it to become a bone of contention but just want to know what the legal standpoint is - is it their problem, can I ask them to get it fixed or do I need to be proactive, get a contractor in and offer to pay half. Im keen to get it done but don't want to pay if I don't have to. Also the damp issue seemed quite pressing to them before the problem appeared to be on their side of the wall. After finding the cracked render they said they were going to contact a friend of theirs to sort the problem but nothing seems to have been done and with winter on the way I would like to get it sorted before the weather really turns!
If anyone can help or offer any advice I would greatly appreciate it.
Thanks
Sam

[welsh brickie]

if they have insurance then they may be able to claim,if its storm damage, wink, wink.Call them first and say you have water ingress due to high winds,after all your both not experts so you dont really know.If its under £500 they usually dont send an assessor.Also get quotes for the work,if the insurance wont pay out then you will have to split the cost as you described "party wall".

[samyell]

Thanks Welsh Brickie, I'll get a builder in to quote and will tell my neighbours about the insurance thing - we have had some shocking windy weather recently :)