Thanks for replies. I think I've messed up then but it's easily fixable. I wanted to tweak the visual setting so that surface attacks in darkness was possible.
I'll figure it out somehow. Typically I spend more time modding than actual playing for a while until everything is subjectively perfect.
I've decided to give LSH a go over GWX before pursuing this fix further though, so maybe LSH is "perfect" for me. Time will show!
Cheers!