All of these coaches are Era 5 models. This era covers the interesting transition from steam to diesel locomotives between 1957 and 1968, with a huge variety of pre-BR coaches still in service alongside new BR Mk.1 and later the first of the Mk.2 designs. Details of the periods covered by the era numbers can be found here. 

In 1957 British Railways changed the principal paint scheme for passenger coaches to a maroon livery, similar to the former Midland/LMS livery.
At the same time each region was authorised to paint coaches for principal express trains in different liveries and re-introduce the naming of locomotives and trains. The former Great Western chocolate and cream quickly reappeared, while the Southern rapidly painted coaches into green, matching the EMU stock. Many new crimson and cream coaches remained in service until about 1960, when these would have needed repainting.
Regional liveries also appeared in general use, as spare vehicles were utilised where needed, often escaping their intended captive service rosters.

In 1964 BR adopted a new corporate livery of blue and grey, though the maroon and regional painted vehicles survived for many years, but slowly uniformity was enforced again. However the use of Mk.1 coaches on heritage railways has seen many hundreds of these coaches repainted in Era 5 liveries, including coaches in service today for mainline charter trains.