Did it have a public phone inside when on trial?
It did. Found the article. (Modern Railways Aug 1993).
2 vehicles were converted. The driving car had 12 first class seats fitted in 2+2 style. 8 were around tables and the other 4 were airline style. The standard class section was unchanged.
The coach next to that driving car was refitted completely in "express" style. It was fully carpeted and had 2+3 seating. A payphone was fitted next to one of the doors.
The seats were the same as used in the 165. It does not say which 465 it was converted from however. (The driving car might have been 64775).
It was unveiled on 13th July 1993 in Waterloo station.