Cheers for the serious responses and yes I did tell a fib, but sorry I wanted to evoke some emotion. The secret to a natural white head on a dark body, for me has been some wheat malts. While to some the body isn't pitch black, it is very dark. I gleaned this from Dave Line's books, who tried to write from the point of view of breweing is a piece of piss. I do believe an "anal" approach to sterilising is required also, by this I mean every bottle and the brewing device is sterilised then filled with boiling hot water. Saying this I have knocked up stouts with darker heads which are not undrinkable but the head doesn't last as long.
Cheers again for responses and just wanted to share my experience over the last 8 years.
Regards,
KIR.