Master cylinder is inside the car, above the clutch pedal. They are very common failures on VAG stuff. Easy to replace but the hardest bit is getting the pipes off, which are engine side of the bulkhead. Mostly hidden by turbochargers and intake malarkey. Usually got at (blind) from passenger side, shove (sleeved) arm under all the intake gubbins. Pipe form reservoir pulls off, the pipe to the slave cylinder has a clip which needs a 90 degree pick tool to pull out when the pipe can then be removed. Youtube will be your friend here.
Changing the clutch itself is 4 hours with a ramp, 6 on axle stands. Gearbox out, which involves driveshafts etc. Strip topside intake things out of the way first though, makes life easier.
Concentric slave cylinder, clutch friction disk and cover plate, dual mass flywheel are all going to need replacing. GSF car parts do a kit for under 500 quid for my Skoda Superb 2.0 diesel. LUK parts mostly, sometimes Sachs. Both are good.
Main dealer quoted me £1100 to do the lot. But that's double what DIY costs.
Thanks but no way am I doing it - crawling around under my own stuff is bad enough, and the way my arthritis is killing my shoulder right now makes it a non starter. If the job comes in around £1100 for everything I recon she will be doing alright.