The wind 'off the clock' in the Twr is always mag because that's the way it's calibrated(usually)and it would be pointless a controller passing a surface wind to a/c on finals in true as it would require a mental calc from the pilot.
I'm glad to see that there is a difference of opinion between what is actually done on the ATIS and what should be done. I can't seem to find any document that states whether ATIS winds should be in true or mag. From a pilots point of view I would prefer it in mag because that's the info I use for initial take off/ landing calcs and at places like Gander it makes a lot of difference.
I get the impression that in the UK, because the variation is so small, no one has really noticed that some pilots think they're getting mag on the ATIS when they're actually getting true.