SEACAM Silver Housing for Canon EOS1DSMkII

An odd one this. I sold a new housing about 5 years ago which has just been sent back to me. It was bought for advertising work but in the event has actually never been used. Condition is not quite as new as there are a very few, very small marks on it from handling, but it remains unused! I'm open to some sort of reasonable offer on this housing as I have no idea what to really ask. It has 2 x S6 flash connectors (I can swap these over for Nikonos 5 type if needed) and an audio visual leak detector. Housing is bare (no viewfinder or port) but complete with original 'spares' kit in neoprene pouch as supplied.