: This is the streaming home for ITV shows; you can search their ITVX catalog for series released in 2019.
: A collaborative service between the BBC and ITV that specializes in archiving older UK series; visit BritBox to search for specific seasons. File Identification Tip Download File D.2019.UK.S03E04.mp4
: The primary hub for BBC content. You can check the BBC iPlayer to see if the series is currently available in their library. : This is the streaming home for ITV
: Many UK-produced dramas and reality shows are hosted on the Channel 4 streaming service . You can check the BBC iPlayer to see
If "D" refers to a specific show like Derry Girls or Dark Money (both of which had active seasons/episodes around that time), searching for the of the show on these platforms will yield better results than using the technical filename.