Open Watch now, pick a service, and use its Download arrow beside the film or episode. The file stays in that service's app for weeks, plays offline and keeps the audio track you chose. No downloader is needed.
How much space
A two-hour film takes about one gigabyte at standard quality and three to four in full HD; a short B movie of eighty minutes takes well under a gigabyte even in HD.
On a PC
Several services offer downloads in their Windows apps too, so a laptop can carry a double bill as easily as a phone.
