144hr hr or 72 hr transit free visa in Shanghai

Myself and my husband are British living in the UK we are flying to Singapore in May 2019 staying a few days then boarding a ship staying at different ports of call before arriving in SH, the port before is Hong Kong . When we arrive in SH we are staying 2 nights in a well known hotel we then fly back to UK from Pudong airport having a stop in Doha for just over 2hrs then continue our flight back to UK.
Are we eligible for the 144 free transit visa and are able to make an application for this before we depart UK if so where can we apply for it please

I am 76yrs of age and my husband is 81 all this is all a little worrying in case we don,t get it right and refused entry

Thank you Jean & Colin