I had my master cylinder rebuilt this summer, and it was easier than expected to remove/replace.
To add to BDA's list, I started with removing the closing plate. It's only 7 small screws, and really helps with the M/C access. I heard that one should not lean on the nose of the car without the closing plate, so just don't do that. The M/C can now be accessed either from below or from the left wheel well.
The lower nut is easy to remove. The upper is locked to the M/C ear and not easily accessible with a spanner, but I found a cheap bicycle spanner that could be grinded a bit and also had to be bent at a weird double angle to fit between the rack nuts and M/C. You'll see what I mean, when you get there...
The push rod clevis must be unscrewed from the push rod and the rod then pulls out easily when the M/C is removed.