Thanks. But didn't EPBs have those seats that run the full width of the train where you can lie down for a nap?
In Southern Railway days, saloon accommodation was only in the end cars, Pullman cars, and catering vehicles of the COR, PUL and PAN families. Everything else was in compartments, with a side corridor only if there was a lavatory in that car. Suburban units (3 SUB and 4SUB) were all compartment until 1946, after which most new units had one trailer with an open layout. From 1948 the motor coaches were also open. The SR design (but BR built) 4EPBs followed the same layout as the last 4SUBs, with one trailer car with full width compartments, whilst the BR design 53xx units had half of each trailer (and half of the driving trailer of the BR design 2EPBs - 57xx) in compartments. Most units were refurbished in the 1980s to an all-open layout. Following a murder in one of the remaining compartment vehicles, the units were reformed so that each unit had either two or none, those with two being restricted to use in the peak hours.
In postwar longer distance units (2HAP, 4VEP, 4CEP, 4CIG, and the two generations of Bournemouth line stock), the first class accommodation was in compartments with a side corridor whilst, with two minor exceptions, second class was all open saloon*. Indeed, other than the sleepers, the Class 442s were the only Mark 3 stock to be built with any compartments.
* Two exceptions: the SR-design 2 HAPs (56xx) and the 4TC Bournemouth trailer units both had four 2nd class compartments