I have a problem with the clutch bleed T-piece; it is leaking hydraulic fluid. I have tried replacing it (this didn't work), I have also replaced the o-ring on the spigot that goes into it at the gearbox casing end, and the o-ring on the bleed screw, this has improved it but it hasn't stopped the leak completely. The only other thing I can think of that might sort it, is the "top hat" seal that sits on the end of the rigid pipe that pushes into the other end of the T-piece.

I've had a look online but I'm not sure if the ones I've found are correct for my car (Octavia Mk1 PD TDI ASZ).

Please can anyone let me know which seal I need to buy (if that is the solution)?

Not to worry, I found the part number, it is 1K0 798 741.

Will pick one up from my local VW dealer parts desk (about £14).