Rupert there are many ways to B&W conversion
1. Channel mixer - run through the B/w presets
2. Black and white - again, check out the presets
3. Gradient map - I personnaly find the first two to give me more options and better results
4. Hue saturation
5. Almost every image also requires some change in the contrast using levels or curves..
However, my favorite is the Nik Silver Efx plugin; this is hands down the best B&W plugin out there.
Send me a few hi-res images to play with and can post some examples...
Rubert, I know your getting an overwhelming amount of advice. I think you should focus on the technical aspects of lighting (it needs to be cleaner) & PP (less & more natural)
Leave the styling & posing too your models...for now.