There is an adjustable linkage accessible from under the car. It connects the short lever, attached to round tube to which the pedal is brazed, to the actuating lever. The only thing this linkage adjusts is the pedal position. It adjusts nothing to do with the clutch mechanism itself.

Undo the locknut at each end and rotate the rod to take up the pedal slack. Then retighten the nuts. Simples. Except that It can be awkward to reach unless the car is on a ramp.

See part numbered 11 on this chart on the Morgan Spares site.

https://morgan-spares.com/4-parts/clutch/

Cheers, Colin