I have read many articles on the subject of Adjusting and zeroing a No32 Mk1 'scope and seen may pictures and diagrams of the tools used in the process, in fact I even process a few of such tools myself, all needs two people/three hands and a fair amount of time. I found the easiest way (For me at least!) is as follows.
Build yourself an adjusting key, I use the word key because probably the easiest thing to start with is an old allen (hex) key. Grind a slot in the end so that it will snugly fit over the end of the adjusting lead-screw. I had a peice of round bar that I ground a slot into and finished with a needle file, I slotted the long end of the adjusting tool but with hind sight the short end would make it easier to use. Mine has some red heat shrink on it so I can spot it when I pack everything up at the range.
Slacken off the ring that locks the lead-screw, I made a temporary spanner using a piece of aluminium plate bent over at the end and filed to fit however you can also grind back a pair of pointed nose pliers to allow a snug fit or improvise.
Now tighten the outer lockring back up until it nips the lead-screw, it needs to be tight enough to hold it in place however not so tight that the leadscrew cannot be turned with the lead-screw adjusting tool you have just made.
I zeroed at 200 on electronics using a front rest on a lovely still day so I did not have to compensate for windage.
once the rifle POA (Point of aim) is the same as the POI (Point of impact) place your adjusting key on the end of the lead-screw and make a mental note of where it points (lets say 7 o'clock) now hold the key in place and rotate the elevation drum until it indicates 2, if the adjusting key moves left/right slightly let go of the drum and set it back to 7 o'clock and continue until it is at your chosen distance. Now repeat the process on the windage drum.
Test fire a group to confirm POI and adjust of needed.
Finally you can nip the outer lock ring up very slightly if needed, be nice to it as it does not need a lot of tension to hold the lead-screw in place.
The adjusting tool