Kick-start shaft

Later boxes had a  different spring , shaft and  inner cover to early boxes .to make  the KS return action stronger,    it seems like you have a mixture of parts .    (edited )

Drilling a new hole could be a problem as the shaft will be case hardened, you risk going down a rabbit hole with more parts but try using this page from Andover Norton to identify the right spring and related parts (it shows 2 springs related to hook position).

https://andover-norton.co.uk/en/shop-drawing/885/amc-gearbox

Parts 72 and 72A are the 2 springs

I have no knowledge of these earlier parts, just good at delving into detail.  

I doubt it possible to mix and match as the spring will either break or bind on the shaft.,The inner cover type that you have should be your starting point . Early ones have a hole for the spring to fit into. Later ones have a stud  that  the spring hooks onto. The shaft and spring then have to match the cover. I think (not sure) that the shaft hole position is diferent on each type.  The later type (hook on) is  a better job and gives a more positive return of the Kickstart, If the bush is worn the early type tends to make  the kS to flick back as you accelerate.

Back in 1965, when I was refurbishing my 1959 99, the kickstart spring had broken so I bought a new one from Lawton & Wilson (My local supplier in Southampton)  The new one was very similar but didn't engage with the kickstart shaft drilled hole.  My Dad ground off the outer case-hardening and drilled a new hole to suit the spring.  Both springs were essentially the same shape - not like the two photos where one has a large hook.