Good to know Chris, I did not think to look at my copy.
Peter that light is precisely what I used. I am interested in the dimensions of your roof vent, it appears narrower than mine which is about 8" x 8" ?
The power supply came up the pillar and across under the headlining by unpicking at the side. No removal necessary.
The wiring was not original to the car, but followed the route of one of the original trafficator wires, as makes sense and suggested above.
The wires across the roof area had been hidden above the original headlining, having been accessed through a small X-shaped hole where the lamp was mounted. The car has a sunroof.
Squeak, there are photos of the roof vent under another fairly recent thread but yes, it is narrower than 8". It is the cast alloy one not the earlier pressed steel version.
I can't remember the details but the wiring for the lamp goes though a hole or two in the wooden frame for the roof covering, hence our suspicion that it hadn't been retrofitted. Who knows. I have learned over the years that there were many slight variations in trim and fittings from month to month.
I have a lamp in my RP identical to Colin's. I recovered it from a 1939 Bedford Duple OB bus in the days when such things were still to be found in scrapyards. We recently picked up a very nice rectangular art deco-style light for Henry's Ruby - £7 on Ebay and also, I suspect, ex-bus.
