I don't see how he would keep the original reg number if they have allocated another VIN but I don't know about it for sure.

The SABT bit means the number has been issued by the Dept of Transport. My next three characters are VRO showing it as coming from a Local Vehicle Licencing office, identified by the next three digiits. The next number shows the year of issue (mine is 0 for 2000), and the last 6 are the unique ID number.