I think most BEA Tridents had pullman seats at the front row with a wood veneer table between them - The Northeast 1E's had this too.
When new, Trident One's had first class seating but was this convertibles?
1968 T1C configs were -
16F 64Y > 16/70
8F 76Y > 8/82
88Y > 93Y (shuttle 100 Y)
The BEA Trident 1C (84 seats 2 class) had a few rows of rearward - facing passenger seats at
the front of the rear Y cabin, rows 9 10 and 11. A facing table seating arrangement in exit rows 12
and 13. In row 12 and 13, the Pax sat up "over the table". In the first class the passengers sat "all across the table "
The front first class had "table seating only" and pax sat face to face.
The Vickers Vanguard and later Trident versions had rearward seating arrangements as well.
T3
14F and 119 Y
or all Y 140 pax (convertible F/Y seats)
T1E 123 Y
T2E not sure of configs
I recall the 2E's and early 1C rear cabin were rear facing rows to the exits then changed to forward facing.
T3's had a rear facing row at the front of the rear cabin
BEA comet with first class sovereign service (10 F + 79 Y)
BEA Vanguard 951 18 F 109 Y
or 953 all Y 132 then 135
Re Channel Airways 1E-140's
I actually flew on that thing. STN-RMI and also to PMI. I was a tad smaller than I am now. We even sat in one of the 4 seaters along with Mum & Dad plus one of my school pals.
It was fine and noticeably much better leg room than an Air Spain DC-8 a few years later. (Worst ever for me was sitting on a Monarch 757 and Virgin Express 737)