BBB +1 Not that I’m excited about it or anything.
British Mountain Bike Series always seems to have kids races in the morning on a much shorter and easier course. Don’t know about the other big enduros but the Bontrager 24:12 has a mini-enduro for kids on a short course a couple of hours before the big race starts 24:12 aqnd BMBS ones for under 12 years or so were also free of charge as far as I remember. Cyclo-cross for kids also good as it’s cheap, the course isn’t usually dangerous and you get to go before all the grownups churn the course into horribleness.