Hi sween, normally when the slave cylinder goes hyd fluid leaks from the bottom of the gearbox where it mates with the engine. I'm afraid its a gearbox off job to replace. however have a check around the 'tophat', its on the top of the box where the hyd pipe enters the box. This can leak and the seals can be replaced with the box on.
If you do have a slave leak check the clutch plate for contamination. If your cars done 80K plus and you are looking at keeping it would be an idea to change the clutch assy.