i've got a somewhat troublesome oil leak which i cant seem to locate.

the A/C pump & power steering pump seem to be showing signs of the leak however under closer inspection the oil level in the PS pump is full & i've been keeping an eye over it for ages (4 months at least).

It's coming from the same side as the PS pump etc. Any other idea's suggestions etc?

Around 1 - 2 months ago i changed my harmonic balancer, would it be possible that i stuffed up the front main seal???

Best way is to degrease the whole front of the engine and run it while watching for leaks.
Often the O-rings in the pwr steer pump fitting have gone hard and brittle just make sure you get the correct O-ring.
I've just done a front cover seal in my 351 rangie which somehow got damaged. It's a C*** of job to do in the car and I tried to find an installation tool but none are available so, I made my own which works perfectly. It pilots off the crank snout and you use a longer crank bolt to draw it in..took about 20 secs to fit a new seal!?

its not power steering fluid.

its definitely motor oil.