Thanks guys.
I believe the donuts are a processing artifact. When trying to reduce the stars one of the actions I use in photoshop tends to do overdo it I find. As I said work in progress
Some of it could also be a bit of star bloat as my camera is modified but I don't have the replacement UV/IR filter in. (I only removed one of the filters and left the other UV/IR filter in the body). So the star bloat isn't too bad currently but I do plan on getting a filter to improve the stars.