Only works when at the Auction House

[Aanson]

I would like to create a macro that only works when I'm using the auctionhouse. I'm hoping that I don't need to settle for [nocombat].

I've tried this:

 /click [target=Auctioneer, exists] MacaroonButton70

.. but it doesn't seem to work.

Anyone got any ideas on how I can achieve this? Am I missing something easy?

Thanks in advance