[Healeys] Chassis number plate question

[Frank]

While on the subject of number plates, I have a question about my BN6.

On the firewall are two plates, one with the "car number" (BN6Lxxxx) and the
other with two four digit numbers (xxxx/xxxx).

Can someone please tell me what the second number plate represents?  Should
either number on the second plate match the "car number"?

Thanks,
Frank