Is A Transit Visa Required?My partner is an Australian citizen and I am from the UK

and we are planning to travel to Sydney from London Heathrow via Beijing. We fly to Beijing with LOT Polish Airlines, we have 15 hours in Beijing before boarding a Qantas flight to Sydney. (1) Would we be able to leave the airport? (2) Would we need a transit visa to stay in the airport? (3) Would we only need a transit G to leave the airport? Would be grateful for response. Thank you. Regards.