Two 72 hour Visa's in two weeks

On the 13/4/17 i am flying London to Shanghai, staying in Shanghai for 48 hours and then flying onto Japan (Tokyo) on the return home 27/4/17 i am flying from Osaka to Shanghai, staying in Shanghai for 24 hours and then flying onto London, my flight is with China Eastern Airlines.

Does anybody see any difficultly in this route, I am worried that as i had only just visited the country 14 days i wouldn't be eligible again, are there any steps can i take before hand for a trouble free transition?