I do not think there is anything such as an Osram H4 LED Nightbreaker. Osram has H4 LEDs, but not with the Nightbreaker denomination. So if Nightbreakers are recommended, it is halogen, for what it is worth. I wouldnt worry too much about the lifespan. Most Mogs have low mileage, so they should last a long time. My Philips Racing Vision has been there for two years, but during daytime I use only DRLs, saving the main lamps.
Then there is the legal issue .Norway is obliged to follow the same MOT rules as the rest of Europe, but they seem to be interpreteded differently. DaveW has stated that when a car is specified with a H4 bulb, H stands for halogen and cannot be switched for anything else, so LED would not be road legal - if I have understood him well. Where I live you can fit anything you like - LED/xenon/HID - provided the car has a headlight washing device and automatic levelling control. This applies for the dips only, if you have separate dip and main lamps. A Morgan has nothing of that, so LEDs are not road legal for that reason too. Again according to DaveW, this limitation does not apply to a Morgan in the UK due to the basic construction of the car. I really didn't understand that, and I apologize if I have misinterpreteded something. My point is, it might be a good idea to do a little research before one makes changes, what is road legal and what is not. Then one might say that you doesn't care, the LED might go unnoticed on a MOT or one can switch LED and halogen back and forth before and after a MOT. Now every man to his own, but I think it is only fair to mention legal aspects too, when we are giving out suggestions, advice and opinions.
And directly to Barry M, if you plan to drive through the autumn and winter in the dark, go ahead and do some changes. If you plan to put your car in the garage for the winter or just drive it on a sunny sunday, leave it be until you get some more experience, have met the crowd, let some desicions and ideas mature in you head, for example next spring. At least, that is what I would have done.
The best mod I have done so far? Changing mirrors.....
