In the restaurant scene, Oliver the vet (Ed Skrein) says he lost track of time watching Game of Thrones. Ed Skrein played Daario Naharis for 3 episodes of Game of Thrones (before the character was recast.)
Beattie Edmondson is the real life daughter of actor/comedian Jennifer Saunders (Absolutely Fabulous, French & Saunders, Muppet Treasure Island) and actor/comedian Adrian Edmondson (Bottom, The Young Ones, Star Wars Episode VIII: The Last Jedi). Saunders appears in the film in a supporting role.
Though the majority of Patrick's close-up scenes were acted by canine actor Harvey, 17 different pugs were used to portray the character throughout the film, not all of them male! At various points the role was played by pugs Foggy, Wesley, Edie, Pearl, Truly, Marina, Glenda, Barry, Howerd, Wally, Nora, Blamire, Entwistle and twins Compo & Clegg! To ensure consistency in the sound of Patrick's 'voice', vocal styling was provided by an uncredited Stephen Lewis.
The ship Sarah & Patrick live on was in the middle of a full-restoration when it was spotted by location scouts. In April 2017 the production team took over, restoring the interior and stripping her brand new white and grey exterior paint-job back to look like a wreck again, so the vessel could be restored as an ongoing plot point in the film. After filming completed she retained her new blue look, including Patrick's paw prints.
The ship Sarah lives on, Lady Doris, is registered as a National Historic Ship, along with just 1,300 other ships in the UK. Meaning she
can fly a special ensign flag to show off her place in British Maritime History. She was made by Vosper of Portsmouth in 1939 as an RAF Seaplane tender, and saw active service in WW2.