The 6-part BBC adaptation of Neil Gaiman's fantasy novel Neverwhere ships to retail on September 9 from A&E Home Video.  The two-disk DVD sports a suggested retail price of $39.95 and contains loads of extras including a full audio commentary by Gaiman, a vintage BBC interview with the author, an archival photo gallery, complete character descriptions and a comprehensive Gaiman biography.   Neverwhere, a dark fantasy set in 'London Below,' a vast subterranean inversion of the metropolis we know, is just one of several Gaiman projects that are all reaching the marketplace this fall (see 'Neil Gaiman's Triumphant Return To Comics').  Savvy retailers who are planning Neil Gaiman displays that will include Sandman: Endless Nights from DC, 1602 from Marvel, and The Wolves In The Walls from Harper Collins, shouldn't neglect the Neverwhere DVD.  Though not all that well known in the U.S., this mini-series should prove to be hit with Gaiman's numerous fans.