Since I was interested myself I did what you might have done yourself and Googled. A single quick search took me to
https://www.motorsportuk.org/wp-cont...icles-V4.0.pdf
One glance at the scrutineering and marshal training required and the rules on dealing with an incident involving an EV makes it perfectly obvious why a club-run Hillclimb dependent on and run by volunteers wouldn't want one anywhere other than in the spectator car park.