For DVLR's marks 1 and 2 the carriage livery was "Olive and Elm" which was, I think quite attractive and distinctive. It was originally intended to suit the DVLR's original loco scheme of brick red with yellow lining. As time passed and I painted more of the locos into GER blue, however the thought of teak carriages was never far away. Teak, however, is a tricky old thing to get "right" and to strip all the paint off the existing carriages to varnish them is unthinkable, however, the GER had a trick up their sleeve, after 12 years or so of re-varnishing teak carriages they would give up and paint the carriage "teak colour" or Stratford Carriage Brown. This is a mid brown. As if to apologise for the downgrade, they lined the carriages with chrome yellow around the quarter lights and black around the waist panels (for those done in a certain panelling style). I've been having a go at applying this to an old GRS W and U carriage side as a test. I'll strip it back and do it properly after.
According to the excellent book "The liveries of pre-grouping railways volume 2" By Nigel J. L. Digby, Carriage brown is best matched to BS 381 489 "Leaf Brown".
A bit of searching gave humbrol enamel no. 9 "Tan" and Revell acylic No. 80 "Mud Brown" as the closest matches so I have tried them.
In thirds, left to right: Humbrol no. 9, Revell acylic No. 80 (both no primer) and far right is Revell acrylic No. 80 on grey primer. The two paints are strikingly different colours with the No. 9 being too light and too glossy when applied - really a little too Annie and Clarabel for my liking! It went on a lot more nicely than the acrylic but the acrylic did dry into a much smoother surface than the enamel. The chrome yellow lining really "pops" against the darker brown.

I then, as you can see, had a go at applying the lining using gloss enamels and a lining pen. My word that is tricky! First attempts (left, on the Tan) were rather wobbly. Second attempt (middle) the paint was too thick, then too thin so the lines became too wide. Third attempt on the right was starting to approach acceptable, certainly applying the 6ft rule. I tried building an edge follower onto the pen but that made the lines worse in my opinion. Those who line their locos and stock have my admiration!

To cap it off, I think I'll go for the scheme shown against the reference I am working from in the book - it is fairly close I think. What do you think?