Ahhh...looking closer you are right....its "RM CDO".
On the record card, it has KOSB (1983-1987), and then its KOB on 13/2/1987...so that makes sense...unless like you say, they had my 101 in 1887, in which case my 101 should be MOT/Tax exempt?
Either way, would that make the wkipedia entry wrong? Would have throught it would be KOB, then KOSB?