Ive owned my TD4 for just under 2 years and since owning it have had a heavy clutch that I had to bleed out about 3 times to get it work to an acceptable pedal.
Its has good days and bad so the other week I decided to order a new OEM clutch master from island4x4. They sent me a Bearmach one - not to sure about the quality of Bearmach but fitted and bled out. Initially pedal was improved but after a week got really bad again.
I decided to go to Halfords and buy a Europat Vizibleed Brake and Clutch Bleeding Kit. Basically just a non return valve, original cost was £5.99 but with my trade card got it for £3.55.
This did help with me not making my usual mess, but take a look at the picture - thought i'd bled out a lump of chewing gum! Never seen anything like this before!

The promised picture

Hi , nor me was that the cause of your problem , looks like it !

Looks like the thrust bearing rubber has deteriated a bit, I also had a few little lumps come out of mine the fluid also looked a bit like coca cola! but without the bubbles.... Just to add aswell I couldnt actually engage my gears at all when I went on a long journey but when the engine cooled down I got a little bit of clutch for about 50miles then it went again once I bled the clutch got rid of all that crud it works perfectly