David - thanks for the explanation and advice. On my board then, I should have each ground connection from each component going separately to the ground pin of the audio input (bottom middle of my board)?
Loud static noise is about what I've got. Had a 4700uF cap across the supply voltage, no difference whatsoever.
Panic Mode - That's a good idea. It crossed my mind a while back to do that, but I thought it might not be something people wanted to bother with. I take up so much time of those who are kind enough to help that I felt like I'd be taking the mick a bit. Anyway, will reconnect the amp built using the old thin-track circuit and get the noise on it recorded and on here ASAP.
Sebi - the board layout is copied from a kit which is available using the identical circuit, where they claim that it works well... so I thought it'd work for me too. I have no SMD parts and wanted to make this cheaply using bits I have here.
Audioguru - you've got keen eyes there and I can't thank you enough for spotting that most embarrassing error!
You really must have taken some time looking over the board, and that is really appreciated. I'm sometimes surprised by how much effort people will put in to help someone they have never even met, it's very nice indeed.
Here is the board with error rectified and with the power input smoothing caps positioned before the IC VCC pin, instead of after it. The circuit diagram is below it too.
**broken link removed**
**broken link removed**
Thank you to all who spend their free time helping me. All the best to you all.