Chinese 4 pin plugs and sockets

The plugs are just a standard 4 pin mic plug. That there is just a standard surface mount instead of a through chassis mount.

Sorry not sure from pic but does it have a single groove instead of a thread? if it is then it is a bayonet fitment, used a lot on army radio gear. Still a mic socket.

AudioSpares*-*Audio*Spares,*Parts,*Cables,*Studio*Spares,*Leads do a range of these 16mm connectors, they are under £1 each part and are the same (ish) as the Maplin ones but at 1/3 the price. You can collect from them (Derby) if your order is over £100.