Right Montie, I'm back. When we used to do the gearbox set upson these, we had a special tool which was basically a hand operated lever to replace the small gear engaging lever on the top of the box. Reason was that the pedal linkage can sometimes inhibit the free movement of the lever, as in your case in 1st gear. What you do is to select and engage 1st gear, without the pedal linkage on, and operated the lever to engage the gear, and to see if it is adjusting up. A fierce lever indicates band linkage going over centre, ie not adjusted up enough, once you are happy with all the gears, you then go back to 1st, select and engage, then connect the pedal linkage and adjust for the correct free play.
Here endeth lesson No.1