Can I use the 72-Hour Visa Free Transit policy?

I'm planning to come to Beijing for 2 days at the end of the year and then I will be flying to Hong Kong for few days afterwards. I'm a British national but I live in Japan so I will be flying from Tokyo - Beijing - Hong Kong. Also, my gf is from the Philippines, does a Filipino national need a proper entry permit to enter China, even if it's for less then 72 hours?