Thank you to Michael R for the excellent drawing of his transmission shift tube (CTL 4959). I've made a copy and fitted it to the Carrier. My existing one was about 1/4" too short and the wrong fixing arrangement so hopefully this will sort my shifting issue.
I managed to fit the lower radiator cowl before I put the engine back in. What a bastard that was! I'm guessing it would have gone in before the axle rather than after it as it took me a while day to get it in and bolted up!
I've also bitten the bullet and bought two of the single pulley uprated truck water pumps as mine are leaking. It does look like you can swap over the pulleys from the old pumps to the new, but I don't have access to a hydraulic press so I'll run on a single belt for now and change them over at a later date.