Fly to Shanghai and join a Cruise

No, unfortunately, you are not eligible for any kind of visa free transit because immediately after Shanghai your port of call will be in Qingdao and this is again in mainland China. Simply speaking, when you have two or more consecutive stops within mainland China, you are limited to just 24 hour visa free transit. Since you cannot perform your itinerary within 24 hours, you will have to obtain a Chinese tourist (L) visa in advance. I suggest you that you ask for a two year multiple entry Chinese tourist (L) visa because UK citizens are eligible for such a visa if they require it. Just ask for it and if asked why, you should just reply that you intend to travel to China more often in the near future.