Gareth.
Your options are;
Original antiques, held as curiosity or ornament, no licence required.
Original antiques that you want to shoot, SGC for the Bess and smoothbore Enfield, and FAC for the rifled Enfield.
Modern reproductions SGC for the Bess and smoothbore Enfield, and FAC for the rifled Enfield.
Modern reproductions that have been properly deactivated, no licence required.
Inert replicas, no licence required.
9mm blank firing replicas, no licence required.
The last item is something that Derbyshire Arms make for theatrical and re-enactment use. They also sell live reproductions and inert replicas, so it might be worthwhile speaking with them about their products. http://www.derbyshirearms.co.uk/
I collect vintage Japanese air rifles & vintage Japanese pellets
Information sought about antique firearms with Japanese markings, do you have one ?