TD4 master cylinder test?

Hi folks,

Is there a way to test the td4 master cylinder to see if it is defective?
Mine is likely to be faulty, but it less than 2 years old an has done 18k.

The RAC and local garage believe it to be faulty as there is lack of pressure in the clutch system for the first inch or so of travel, but i dont want to spend cash on changing it and find out that the slave cylinder is actually at fault.

To buy from LR and fit at local garage is £235. Obviously i dont want to spend that cash if the part is working properly so is there a test that can be done to diagnoise if it is faulty or working fine?

if possible see if it splashes in reservoir when pedal pumped this means seal are poor ,and black fluid or deposit on bottom of reservoir means the same, normally you can also make slave pipe with bleed niple one end and replace pipe from master cylinder somewhere before slave so that master cylinder can be bled and isolated pedal should be hard and not sink ,not so easy on fl