The serial number is stamped on the underside of the chassis. To find it, place the set face down and look up to where the tuning indicators slide. On my example here, it's near to the FM tuner. Additionally, some sets still retain their paper sticker on the turntable, but the chassis is obviously the reliable one.
The sockets can be found at Partridge Electronics:
http://www.partridgeelectronics.co.uk/03Bconnectors.htm
Aerials are rather more tricky, sadly...