CJO = Chatsworth made Oct 1980 so it is probably a full cro-mo (Either a Team or a Supergoose)
The 345392 is the actual serial number (depending on the order of the numbers that you have quoted)
A pic would help of the frame and the number layout under the BB
The rest 24 and BH216PL is probably a house number and postcode so why not trace the original owner!
On second thoughts don't as it might have been nicked BITD!