It could have been anything! No point speculating too much. If EN8 will do the job, then I’ll use that and some phosphor bronze too. It’ll be nice to work with some bronze as it’s new to me!
i have been researching more this evening and found a picture of a later model gearbox which aligns with the rebuild thread. However, it looks like a different shaft; mine is still just plain hexagonal. So maybe this is a model after mine?
I will reach out to the person who posted it on that different Forum and see if they can share the full manual.
Judging from the gearbox picture, it looks like the fork holes are on the same plane, so it may be easier to make than i imagined.

Also, in other good news. The other site near me at work has one of the later models of drill press, so I will enquire with the maintenance team if I might be able to take it to pieces and take some measurements!
I have also tried to contact a few employees of Meddings on LinkedIn to get some contacts, but I doubt that’ll go anywhere. One drawing would make my life a lot easier! (Yes, I can do it without, but it’s always better with the real drawings)