Just to let everyone know, after monitoring the temperature of the the
PSU and the air emanating from it, and seeing that they were booth
essentially room temperature, I removed the fan (realizing the safety
implications astutely pointed out by w_tom).

The PSU is a /little/ warm to touch now, but there's very little heat
actually radiating from it, and it's still completly comfortable to
hold. It's been on and powering the device for over a week now, so I
think it'll continue to be fine.

Thanks for the advice,
Jamie.