The British Film Institute has published a 2 minute video of the Selsey Tramway in operation.
https://player.bfi.org.uk/free/film/watch-the-selsey-tramway-1928-online
The main scenes depict the Sheflex railbus travelling towards Selsey along the embankment on the west side of Pagham Harbour; then arrival at Selsey Town; and finally arrival, change of passengers, and departure from Chichester.
If you click on the ‘Related’ link, you will find other rail-related ‘shorts’, including a 1966 walk along the trackbed from Maldon West.
(Jeff Vinter)