Ok, an update, the cracked pickup ring was annoying me so I swapped it out for a new one, not a difficult task but fiddly enough that it is a job I never want to have to do again, I sellotaped the bridge in place to keep it from shifting when I removed the strings, seemed to do the job ok, also had a moment where I thought the pickup ring was slightly too small and I was gonna have to screw the old one back in but turns out I just had to use a little force and push the pickup inside the ring, makes sense since Hofners do not use foam or springs to raise the pickup to the required height.
Replaced the tuning keys with a set of the rugby ball tuners , tuners where pretty much a drop in replacement apart from the holes where lined up very very slightly different so I had to angle the bottom screws very slightly but once screwed in it all looked fine and the new tuners are much more solid and accurate than the awful Wilkinson tuners.