After further examination today in the daylight. it is leaking from behind the pulley, not from a hose, and appears to be leaking only when actually turning the wheels.

This started after I had changed the fan belts, so is it just a case of over tightening the power steering belt? Or is it bearings etc that will leak even if I slacken the belt a little? Can the seals/bearings be replaced? And am I likely to of damaged the pump or rack by losing the fluid?

cheeRS