Kunming 24 hours visa

Hi just want to clarify something. is Kunming China offer 24 hours twov on arrival. My ticket is Kuala Lumpur to Kunming, at 9pm 27th of August , stay over for 7 hours and then from there to shanghai Hong qiao and arriving at 1pm and using UK passport. Do we need to go out at Kunming Airport when arriving there and redo our check in at Kunming to Shanghai Hong qiao. On the 29th of August 9am we will go to London. Do I need to apply visa before travelling? Thx