Ok. I just found some time to get back to this project. I've simplified it to use as a stereo volume control, between my satellite TV receiver and the hi-fi. The problem is, the damn thing is whistling at me. It's ok until the powers switched on. Then this whistle that changes pitch as I move my hand over the circuit starts. If I remove IC1, the IC2 side works fine and it's the same if I replace it, and then remove IC2. Is this something to do with component placement on the PCB/breadboard i.e. certain components to close or too far away from each other?
Thanks
**broken link removed**