Thanks Phil.
I was tempted to replace the spring but it doesn't look like there's anything wrong with it at all.
Managed to get the spring back in without the "Special tool", used rope and this video for help:
I didn't manage to figure out how to turn the cam without removing the chain. I removed the sparkplugs and could only shift the cam a tiny bit clockwise and anti clockwise but then got worried I might damage something so left it.
I'm going to take my chances and clean it up, put in valve cover new seals and put it back together. Hopefully get that done today if the rain stops and will try firing it up. Fingers crossed!
Thanks for the tip on the oil and filter changes, will def do shorter intervals.