[Louthcoombutt]

I'm not quite understanding the situation of your sink jj, but if you're in Adelaide (I have some vague intuition you are) I could easily swing you some acoustic insulation such as is used on sewerage pipes in high rise buildings to dampen the noise of flushed poo. It comes in sheets, 25mm thick. Esseltecdi at gmail dot com if you want some. Let me know here too, as I only check my emails infrequently.