Looks great Simon, well done, such a beautiful area this one, up there with the belt and sword of Orion, Rho Oph and Vela SNR I recon
As to why we don't image it more often down here, good question, probably only because of its size and declination, parts of it barely reach 40deg above the Northern horizon for most of us, so we tend to over look it, including me.
Mike