24 hour Direct Transit in China (24 hour TWOV)

Hi,
My wife has a Bangladeshi passport (I have British). We wish to travel Denpasar (Indonesia) - Bangladesh with China Eastern. Routing is showing 23:30 layover in Beijing and we wish to avail a 14 hour Mutianyu Great Wall, Tiananmen Square and Forbidden City tour.

I understand that we can both benefit from 24 hour TWOV and thus DO NOT need visas in advance (G or L). Is this correct?

Thanks.