Today I achieved some improvement.
First removed the clutch arm for inspection. I found that it's a little bit worn, so I welded up the ball and rasped/sanded back to fit in the plunge.
I think I'll put a new arm to the basket next time at MiniSpares.
Next I dismantled the master cylinder and despite that I did not found any fault I've installed a new repair kit - just in case.
Bleeding time.
Finally I followed another tutorial for setup the clearance. It says : screw the bolt until it touches the arm, then turn it back one flat.
I am not sure it will be the final stage as I don't know if the release bearing will 'like' this but it works. I can select gears more easily than before, so I drove a round in the city without any documents in my pocket 
I measured the movement of the pressure plate, it moves ~1.5 mm at fully depressed pedal.
Tomorrow I will check one more thing. At the moment I can depress the clutch pedal all the way to the floor - carpet not installed yet. With the carpet in I will lost some mm movement, right ?
What if I weld up the hole in the pedal where it connects to the master cylinder and drill a new one a little bit above the old hole ?