Clutch sticking

Hi, hoping you can help please. I have the TDI model. A few weeks ago the clutch pedal started clicking (out of nowhere) and since then it does not release fully after being pressed (only comes up about a quarter way, to around the biting point). Other than that, car seems to be driving and changing gears fine.

I brought it to one mechanic and they told me that I need a new clutch kit, a new slave cylinder because it is inside the gear box, and that I might also need a new dual master flywheel, but that they would not know for sure until they took the clutch apart.

I learned from calling a parts place that the slave cylinder in my car is actually outside the gear box, so should not need replacing when changing the clutch (unless it was leaking, which it is not). I relayed this information to the garage, who confirmed that the slave cylinder would not need changing as it was outside the gear box.

After this mistake, I decided to get a second opinion and took the car to a different garage today. The second garage believe the problem is with the dual master cylinder and that the clutch "seems" fine.

I honestly do not know who is right and what to get fixed, and cannot afford to end up in a situation where I go for the wrong fix and end up having to get the lot done.

Any advice you can give would be fantastic help. Thanks in advance! Kate