Marston Three barrel deringer, cal 32 RF RARE 4 inch barrel

Marston Three barrel deringer, cal 32 RF RARE 4 inch barrel . Flayderman P. 491, item 8A 075. 
Approx 3300 made, of which only a small % (believed less then10 %) had a 4 inch barrel. Standard was 3 inch. 
So here is the rarer one. 
Excellent condition, barrels have a muted dark grey/ blue matted patina, rifling is very sharp but also a lot of light pitting.  Markings on brass frame are perfect,  The selector on the left side works perfect, same for firepin.  Grips original to the gun, no damage, most of varnish present.  100 % correct and good shooter.