[Edited again to add: I now think I was wrong in what I said in this post, but it continues to be among my most-read posts. I have left it here because I don’t want to appear to be hiding the fact that I have changed my mind about this]
[Note: after a number of helpful comments (see below) I have revised my opinion about this. Please continue to use Evans Cycles as you see fit :-)]
Consider a typical bicycle light. It’s a small battery-powered light, easily fits in a pocket and just as easily dropped or lost. It unclips easily from its mounting bracket so you can take it with you when you leave the bike.
So there are two components to your typical bicycle light: the light itself and the bracket attached to the bike. Which do you think is most likely to need replacing? The fragile light that you are constantly transferring from place to place, or the sturdy bracket that never leaves its secure attachment to the bicycle?
Don’t make the question harder than it sounds. The correct answer is the obvious one. Ninety-nine times out of a hundred you will lose or break the light before the bracket needs replacing.
Can you, therefore, go to a cycle shop and buy a replacement light for your bracket? Don’t be silly, of course you can’t. Can you, on the other hand, go to a cycle shop and buy a replacement bracket for your lamp? Why yes! How fortunate! For that one time out of a hundred when (I don’t know) a heavy piece of street furniture snaps off and smashes your bracket, yes, you can go to the cycle shop and get a new one.
That must be why the cycle shops carry so much stock of brackets. All those bits of heavy street furniture that are constantly breaking off and smashing light brackets all over the place.
Or perhaps its because the FUCKERS who STEAL lights off unattended bicycles can go in and get a cheap replacement bracket to attach the STOLEN lights to their own, probably STOLEN, bicycles.
Do not buy stuff from any bicycle shop that stocks replacement brackets. Evans Cycles, this means you for a start. Any others?