That clevis pin - like many on a mini - gets ignored during maintenance.

Another clutch part often missed during lube jobs is the ball on the end of the clutch arm - where it slots into the thrust bearing shaft in the "chinese hat" ( next to Hunter2's favourite clutch throw-out stop lock nuts ).

Yes, chuck the throw out stop nuts (or put them in the bin).  They are only useful for drivers who will not disengage the transmission at red lights etc.

Could not shift gears in Iowa while looking for fuel in a small...can't remember the name...town.  When we got to a fuel pump, I said, "If I can't sort this in 15 minutes we have a problem."  Well it didn't take 15 minutes...the stop nut had walked in, so off it came & into the parts bin.

By all means eliminate faulty bits. 

PHOTO: this was the pin that came out of ROO...after just 2 1/2 years in use.

IMHO the only ways to lift the pedal is to take out all the slack/wear (or at least as much as possible.  The low hanging fruit are the pins (not forgetting the holes - new pins in an oval hole won't buy you much) at the top and bottom of the clutch arm.  Next is the ball on the end of the clutch arm... Then the pin between the pedal and master push rod (again...and holes).  Lastly is the hole in the release bearing shuttle (have to remove wok to access).  Bending the pedal and lengthening the MASTER  push rod are the only other options..

Well there's one more option ... Having a modified clutch setup I was having trouble with getting enough travel and this was solved by my Guru finding a slave cylinder with a reduced bore.. I was told it came from some kind of Holden (Chev to you)..but that was over 30 years ago so good luck in finding one like it....

Removing the clutch arm return spring with obviate any "adjustment" issues and getting rid of the overthrow nuts takes them out of contention.

IF slave piston is running into the retaining clip and restricting travel then a longer slave push rod will help ..otherwise fergedabartit..

Cheers, Ian

Adjusting the stop nuts inward only reduces the distance the clutch can actually be disengaged once the pedal is fully depressed.
If your pedal has to go a long way before releasing the clutch, the cause is most likely wear. Start by eliminating slack in the release mechanism, starting with the clutch return stop - the small bolt on the outside of the clutch cover which pushes the long lever outward. It needs to have a bit of  a gap ( the 0.5mm +/- mentioned above) so the clutch isn't left slightly disengaged. Note you adjust this while pulling outward on the lever to take up ALL the slack. Once you remove the feeler gauge you should have the correct amount of slack, a very slight wiggle.
If this adjustment doesn't solve the problem, you need to check for wear on the pivot pin of the arm, on the round tip where it connects to the plunger, on the plunger itself and (less likely) the trow-out bearing. One other pin to check is the pin the pedal itself pivots on. Once all the mechanism is corrected, and you still have a problem, then most likely the clutch plate itself has worn down and needs replacing. 
There is a very remote chance your clutch lever got bent, but bending it from its designed shape to fix a low pedal is the wrong thing to do a it just would be hiding other problems.
With everything correct, you should begin to feel the 'pressure point' in the clutch pedal approx 1/4 down the total pedal travel.

While we're on the subject; the clutch on my Mini engages and disengages all the way down at the bottom of pedal travel, literally at the floor. I've adjusted the double throw-out stop nuts by tightening by a few flats, but it has not resulted in much of an improvement. This is a pre-verto if that makes a difference.

Suggestions?

I agree with Dan... the 1/2mm measurement referenced should be for the throw out arm stop bolt adjustment.  Take that 1/2mm spec with a grain of salt.  It CAN be tighter.  If you feel you have excess pedal travel, close the gap a little bit.

Without consulting my Haynes, I believe he was asking about the small bolt that holds the clutch lever out to remove excess slack.
I do like Alex's comments about the relative usefulness of the various Haynes editions... truly a man of experience.

The overthrow nuts are a royal PITA - I nearly had a nasty when they wound themselves in on Tubbs and I couldn't disengage the clutch while doing *70mph* up a motorway sliproad...

Which Haynes do you have ?

The later dark blue one isn't much use as it isn't very absorbent, best to just sit on it to prevent piles on a cold floor.  The earlier light blue, tan, or purple ones are much more useful.  The orange Leyland manual or a BMC folder are excellent.

THROW THE NUTS AWAY they are not needed and will only cause you problems I have been running without them for a very long time on several different cars with no problems .

Anyone know what the clutch return stop gap should be? Haynes says "...slacken the locknut and adjust the stop bolt until the specified gap is achieved." Fine, but I swear I can't find where is says what the gap is supposed to be. Mine's a pre-verto clutch. Thanks!

[EDIT] Never mind. I found it. .50mm. Maybe is just me, but I have a heck of a time finding things in Haynes. Very odd format for a reference book.