All the scenes in the film set in Donald Crowhurst's house and gardens were actually filmed in the real house. The production moved into the house and shot there for several days, including in the Crowhurst living room, bedrooms, study and grounds.
The pictures featured at the end of the film are of Donald Crowhurst's actual boat, the Teignmouth Electron. The producers commissioned a photographer to travel to Cayman Brac in the Caribbean to record what remains of the actual trimaran in its final resting place, anonymously rotting away, forgotten, on a strip of rough beach.
One of two biopics about Donald Crowhurst slated for release in the UK only a few weeks apart. The other is The Mercy (2018), starring Colin Firth as Crowhurst. Crowhurst was finished earlier, but the distributor of The Mercy (Studiocanal) bought the distribution rights and delayed the release until the month after that of the other film.