57 (08) 1.8TSI - Clutch replacement

Hi all,

So I recently took my Octavia to the local Skoda dealers to get the stiff gear change looked at.  They came up with the diagnosis that the clutch is on its way out and needs replacing.
(This is part of an ongoing series of problems (detailed in another thread) which I am trying to get resolved ideally under warranty or with the dealer I bought from.  Things do not look too hopeful at present.)  

They quoted around £730 for a replacement.  I'd rather not take this route, preferring to (if possible) source my own clutch and have my local independent garage fit it.

So the question is, which clutch do I go for? I've seen Sachs and LUK clutches listed, however I understand that the clutches are not interchangeable between the two brands?

How do I find out which my car has?  (My car has the BZB engine).

Does anyone have any further advice on the matter? 

Many thanks..