MonkeyMan

I having problems with noisey neighbours and I'm thinking about soundproofing my party wall on one side. I've been looking for infomation and have found two websites Bicester Soundproofing Products and Soundproofing Forum

Does anyone have any experience with them or thier methods?

I'm not an expert but I would guess that the damp is from the moisture in your kitchen condensing in/on your cool external wall. If the spot in the picture is above the hob then thats probably what it is .... I'd still get someone with experience to look at it. I could also be some exterior pipe work dripping down the wall.