I thought it might be useful if I record a diary of my experiences getting the various licenses as and when I need to. Not only to share for others but also to get input from anyone here with experience.
So quick update number 1.
I've reached out via email to my local ELO and he has replied. My initial request was probably too much in one go because I have other interests in clay shooting, I have that cannon and I was also interested in a rim fire .22 for vermin control. I also mentioned model rocketry.
Main areas of difficulty seemed to be the FAC license and the rocketry actually which surprised me. I've replied and stated that if it makes it easier then I'd be happy to focus on the aspects that are more important to me. I have asked about the BP A&K for experimentation (I also explained about the new precursor legislation as I wasn't sure he knew anything about that). The second request was on how to license my cannon for use with BP etc. If that is a shotgun license then I asked whether I needed a gun cabinet for it. Not sure how I'd fit it in a cabinet as it weighs 35lbs and is a rather odd shape lol.
He gave me info on the MSER case for the BP so that seems like a pretty simple part of the application process.
I'll keep you all posted.