Doors open at 9, not 10 and as it's free entry there's no tickets to check so queues move very quickly. Depends how long the queue is that you join but it won't take long at all to get in.
Thanks, i knew doors opened at 9am, 10am was the latest time i was expecting / hoping to get inside, once i'd arrived at 815/830 and queued.
But your reply suggests that i should get in sooner , so thanks