At 36 minutes: just after Fiver's vision of the red car (and his and Dandelion's close shave while crossing the road), the rabbits make their escape by running under a park bench. The bench has an memorial plaque with the name 'Richard Adams' clearly visible. Adams wrote the original book, Watership Down.
Lee Ingleby (Captain Campion) & Jason Watkins (Captain Orchis) also worked together on three episodes of Line of Duty (2012) as Nick Huntley & Tim Ifield respectively.
The rabbits are hiding under a park bench while Fiver is examining the red car. The bench has a memorial plaque for the author Richard Adams.