Your link Robbie is to H4 fitting LED replacements for halogens. My understanding is that many such fitments leave illegal lighting as you are relying on the OE reflectors and or lens pattern optimised for dual filament halogens.
Exactly. They use the reflector bowl and lens designed to manage the light from a halogen bulb. I fail to see how they can be so much brighter without producing dazzle.
Go for properly-designed LED units by all means, but I have reservations about these.
How many of us drive our Morgans at night so fast that we need such lights anyway?