Thanks Anders, that's very helpful, and I’ll experiment soon.
Until now, I used to copy the VIN number into the space provided at the top left.
One search shows the equipment list of the car, and it’s got some mistakes in it.
The Xantia had to go; I couldn’t make time anymore for all those LHM return leaks caused by hardened and brittle hoses.
I’ve now got a C5 VIN VF7**************[VIN obfuscated, can be read by forum staff] … quite a barge compared to the Xantia, but it’s absolutely fabulous at high speeds.
Welcome back, by the way.

While you had your back turned, some of us snot-nosed brats have had an orgy of wandering off topic with impunity.
Malcolm and Adam,
Yes, the bulb is soldered into the holder, making one piece.
None of the dimensions are critical, and the 47744 bulb has twist-lock contacts on both sides.
http://www.narva.com.au/products/browse/globes