The problem is not just a matter of the bulbs. As you say changing to LED bulbs would be fairly easy. The real issue for me is the really poor quality of the unit as a whole.
If the bulb holder gets too hot the plastic insulation can give way and the centre contact drops back and looses contact with the bulb. Then there is the issue of the screws that hold the lens. If you are lucky you get them back in, if not you can struggle for hours and destroy the threads on the brass screws.
I would even think twice before fitting them to a trailer let alone a car!!!!!

Peter

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