Chris- sorry to be off-topic, but I can't help to be curious about your writing style (after having read some of your previous posts as well).
Assuming that English is your native language (since you're in the UK, and have a very English-sounding name), I'm wondering if you intentionally write in disjointed sentences without much regard for proper grammar.
I mean no personal disrespect. If by no fault of your own you happen to write the same way you speak, I'm sorry if I offend you with my questioning.
on-topc: I think the only way to bring back color information in a B/W image, is if you have a photo originally shot in RAW format. Even if your camera was set to B/W the color info would still be there. With a jpg or tif file, no less of a scanned photo, there would be absolutely no color info embedded in the file.