Hydraulic Clutch Fluid Pressure?

I hear what you're saying above
surely if you can get fluid tothe master ( jerry rig a bottle with a hose, splice it to the master inlet ) it will prove the master and or the slave is rooted, I'd want confirmation of which or both before ordering parts
I can see a scenario of a knackered master which caused the original issue and a g/box being pulled for no real reason ( and new parts on the bench waiting fitment )
the issue will be can you get fluid to the master via existing ( even shortened) pipe - almost like someone dropped a small ball into the master inlet port then fitted the pipe - allows air to come back but stops fluid entering

hey, outside the box here, grab a clutch master off the wreck out the back,G clamp it to anything you like so you can work it ( under bonnet by hand or armstrong etc) fit the csc to that, confirm the csc works or leaks or doesn't work, should be able to hold the clutch in for 15 minutes ( smoko time ) without loosing pressure, take about 30 minutes to fit, one compression coupling

Personaly i'd still fly by the

!Seat of the pants!

I.E. i would warm the french letter up and fire it up in gear and go for a drive- with a damn fair few activations of zee clutchen and brakzeen french poodles TOGETHER.
Reality IS if! it's been sitting and has frozen a clutch plate to a flywheel then well!
What have ya got to lose! As ya said the .
Pedal FELT all right- and you have alluded to a rather weird system that in reality seems un bleedable- in normal terms- therefore with it-!Feeling all right!
The only effective problem is.
a clutch frozen and not releasing.
Which CAN happen-(Agrees with skin)

Incedentaly the air and **psshhh**
Well at 100 P.S.I. air pressure- tis air it
WILL NOT hydraulic out a siezing brake caliper piston.
A grease gun WILL without any **pssh**

If as ya say irrespectively the pedal *feels* okay and the clutch is not releasing i would drive it first before pulling it apart.