Hi All,   Does anyone know the difference between the MK2d, MK2e and MK2f coaches (1st and 2nd class). I have searched the internet but can't find any info on this (maybe there aren't any differences!!  ).    I am looking to know whether there are any underframe / body detail differences, and interior differences as I would like to make my Graham farish examples as accurate as possible for my Cornish N scale layout. Also, what was the interior colour scheme for these blue/grey examples runni