Factory Build Dates

Having had quite a bit of interest in my gearbox letter in MMM, it appears that the delay in leaving the Sevel-Sud factory and date of first registration is quite widespread and shocking.

I've found the 4 digit build code and the website that converts it into a production date without contacting Peugeot UK.
Does anyone know where this 4 digit code might be on a 1998 Boxer chassis ?

The website covers all PSA vehicles and the code for my C4 Picasso is on a label on the drivers door frame both codes match info from Peugeot/Citroen UK.

Terry
(ps still looking for a Berkshire Motorcaravans Handbook wallet, someone is sending me an original keyfob from that now t dealership, now Marquis )