Brown flour always used to be bleached and than a colour added - so not especially good for you.
Brown , wheatmeal , wholemeal , wholegrain , all have minimum percentages of the grain left in.
The more of the grain left the better.
Will do some research and get back to you.
Checked in a recipe book, and old trade description act says :-
wholewheat bread 100% wholewheat flour
wheatmeal bread 80 - 85% extraction flour
or look here http://www.bbc.co.uk/dna/h2g2/A2198586