Does anyone know the Plus Four LED headlight manufacturer and can these units be fitted to a 1983 +8?

Wolf Performance do some led headlights but not the same as the Plus Four https://www.wolfperformance.co.uk/lights.html

I believe Peter J of this parish has some very similar if not the same. The dealer Krazy Horse in Suffolk often retro-fits similar so another possibility if you don't like the Wolf ones.

Try a look on EBay .Lux. Ones in chrome and Black as supplied by Wolf . Bowers have a number too ,the factory ones are very expensive ,also used by Caterham in 5.3/4 size also very expensive .
Truck light do a very high quality one too at a much better price . So lots to chose from just avoid the cheap ugly Chinese copies.

Or bettercarlights they do T bar leds about £330 a pair legal in UK

The LED lights as fitted by Morgan include a Daytime Running Light in the cross bar.
The ones I have come from the same Chinese source, but a single LED cross bar that is wired as a sidelight.
They fit in a standard 7" light housing.
I got mine from Just Add Lightness, they are a Caterham specialist.

https://justaddlightness.co.uk/product/caterham-7-led-headlight-upgrade/?v=79cba1185463

Not cheap, but they have passed 2 MOTS and give almost as much light as the LEDs on the Mercedes!

Reading the spec., these look like 5 3/4" units in the link. Don't we need 7" ? - have I misread something?

Paul,

they had both, can I suggest you contact Doug Taylor at "Just Add Lightness" to enquire?

Peter