Yes to the first question, though Gunfire need to be given your UKARA number otherwise customs will seize and destroy it when it arrives in the UK. A contact number on the packaging also helps massively if there are any issues.
No to the second question if you mean this shotgun:
http://www.patrolbase.co.uk/airsoft-shotguns-and-grenade-launchers/franchi-tactical.htm#.VWszE9m9LTo
The Maruzen M1100 is a gas operated shell ejecting shotgun. A lot of fun but very impractical unless you hire someone to pick up your shells for you. The ASG is just a regular single shot spring shotgun. Nothing special - just very cheap. The fourteen shot shells are also very poor quality. This is very much a CQB gun though it has the same heavy pump as a trishot making it pretty pointless really. That said it is very light so makes a great secondary weapon.
Edit: Elaborated a bit more.