Actually shoota, as the clutch wears, the diaphragm moves further away from the flywheel as it wears,

Also, the fluid should not really move much at all when the pedal is depressed, nothing noticeably anyway.

As for the symptons, sounds like a naturally worn out clutch. High release and slippage point to a friction plate that has little material left or that it may have a pressure plate that has not enough clamping force. Perhaps the wrong pressure plate was used to start with.

I had a similar issue with my celica 5 speed behind an A-series although cable clutch. Pedal take up point came out further and further but still was not slipping. Adjusted the cable lasted a day or to before it pretty much let go all together. Slipping badly. Pulled it out to find the diaphram buggered.

You're right Don, it does.
My bad.

so there is no noteable fluid drop when pressing pedal so that is good. starting to get some slippage in 2nd and 3rd now.

is it just coincidence that the clutch has gone after the master was replaced? so how do i id. a replacement? will it be readily sourced? is it likely to be just the plate? and can i diy this?

what's toe clearance?

It's just coincidence that the clutch is gone after the master cylinder. Do you know if the clutch was replaced when the engine was installed? It could be 150000kms old for all you know.
Ring ABS or Repco and get some prices. You will need a full clutch kit.
Make sure you know the model of the car that the engine came out of and the year it was manufactured.
It should be only a few hundred for parts.
You can DIY if you know how to pull out a tranny. The main thing you might have trouble with is aligning the clutch upon reassembly. It's pretty cheap and easy to find a clutch aligning tool. Don't try without one as it can make life very difficult if it isn't properly aligned.
It's not a hard job, just time consuming and fiddly to do on the ground. The bigger the transmission the harder the job.
Good luck!