Interesting interior BEP pic here from latter years - 2003 it says. Couldn't find an image pre-refurb with a more original interior on my cursory look
and exteriorThe redundant former buffet area in South West Trains class 412 4-Bep unit 2322. 1st August 2003.www.flickr.com
Not sure if it's a buffet unit, but there's some nice interior footage of the pre refurb CEP/BEP stock in the episode of The Professionals; A Stirring of Dust.
It's on ITV player at the moment.