Return to China

Hi, I lived in China for 15 years, and had residence status but unfortunately the pandemic circumstances led to a repatriation to the UK in 2020. My residence visa status expired in 2021. I want to return to China on a tourist visa, but not on any official tour, since I will stay with friends in my old home town. How would I get around the issue of requiring an Invitation Letter from a tour company for a tourist visa ? What's your suggestion ? Also, can I book and pay flights AFTER my visa application is approved as long as I provide an itinerary for my trip.