Hi Pete, Google; 'Brass Quarter Turn Mini'. stop cocks. Should find a suitable single unit via any good plumbing outlet. These are like a mini 'Pillar' tap without the high centre spout mount . The quarter turn usually indicates ceramic disks but they could also be an O ring.....It is easy to add a piece of chrome plated copper spout and the suppliers should be able to give the required lower bezel and female nut to suit the outlet.....
KKatchya KKromed...............Jim.