Interesting. This morning at 10:33am BST I was being bounced with "Sorry" and the usual click.This is on the regular line, two more weeks until I make silver.
Then at 11:00 I called again and it went through to an agent in a couple minutes. I happened to mention that I had had trouble getting through and he was really surprised. At first he assumed I meant in the evening ("because we get all the US calls and it's a big country").
But when I mentioned I wasn't able to get through around 10:30am he was shocked. He said there there had been basically nobody in the queue since 9:30.
So it sounds like something was actively broken with the call handling system, not just that they were busy. Hopefully it's fixed now?