Ali,
I've obtained a domestic CCTV survellience type camera with sound and will bring a small TV but it will be practical to set it up before hand to see a)if it functions, b) we can find somwhere to install it, c) consider the H & S implications, wires etc.
As I said it may not be practical to set one up, do we have access to the civic centre on Thursday night, if so we can give it a trial run, it may be that it only picks up sound from the back of the room. If someone else has a TV I can let you have the camera before then