Hi arran,

uncheck all the layers you don't need to display the beard. Then you go to SELECT/COLOUR RANGE, a little window pops up. Set the button at the bottom to SELECTION. Now take the eyedropper and click on the beard area. In your preview window you should now see white what will be you selection. You can tweak it by changing the fuzziness and you can take the PLUSeyedropper and add to your selection if needed. Obviously the minus substracts. Now hit ok and hopefully your beard is selected.
If you still couldn't get it quite right and some parts are missing. I would while the beard is selected go to LAYER/NEW/LAYER VIA CUT or apple+J. That cuts your selection and puts it into a new layer, so you can give the rest of your beard a finetune, without affecting the bit you already have.

good luck