Thinking of returning

After around 8 years away, I'm thinking of returning to marshaling. I'm completely happy to 'start at the bottom' again, at least in the eyes of MUK and really excited thinking about getting back at it.
Mostly Donington previously (albeit under different ownership at the time) with a bit of Silverstone and Malory thrown it (Midlands based).
What I'm really interested to learn is; what have I missed, what's changed and what do I need to know?