I appreciate the feedback from all of you.
My main consideration had been using this as an opportunity to fit a bulb type that would be unlikely to need replacing again, as it seems the constant dimming gives the original lamps a shorter life. I already had doubts about potential technical issues (‘dimmability’ and CanBus feedback) – but as you have pointed out there are other issues:
Physical sizing of the LED lamp
Light spread and direction
Reflector efficiency and focus is based on OEM lamps
Colour temperature
Legality
Visual impact on oncoming drivers
In view of the above I have decided to stick with regular lamps
I’ll mark the topic as Solved on the most recent comment. Once again, thank you all for your help on my first post here.