They're not too bad, some people quote about 30 mins, which I found unrealistic, you need to remove the rubber pipe from the white plastic pipe which carries the fluid to the master cylinder, if you can clamp the other rubber hose at the bottom of the fluid reservoir, it should prevent fluid going everywhere.
It has a clic-r clamp, which requires special pliers to remove and refit properly, and is a bit of a faff. The rubber hose joint to the white pipe was ridiculously tight, so I just sliced it off carefully. Might be worth having a foot or so of standard fuel hose to replace it with.
Unclip the metal pipe from the back of the master cylinder, space is tight, but it's not too bad
Look at the clutch pedal, at the top, you can see the pushrod, you need to remove the metal retaining clip and washer, taking care not to drop them down the back of the footrest!
Remove the 2 13mm nuts and you can withdraw the master cylinder. Put something on the floor in case you have any fluid leaks on the carpets.
Fitting is the opposite of removal, then bleed the clutch as before.