It really depends on the period.
By the 50's these coaches were no longer top link and would have gravitated down to secondary services behind N15's, N's (especially in the West Country) and BR/Fairburn 2-6-4T's for a very short period.
Prior to this, you could use them on all SR top links with MN's, N15's, V's and any multitude of pre-grouping express locos.
However my personal favourite will be a three car set behind Hornby's forthcoming T9 somewhere west of Exeter.
By the 50's these coaches were no longer top link and would have gravitated down to secondary services behind N15's, N's (especially in the West Country) and BR/Fairburn 2-6-4T's for a very short period.
Prior to this, you could use them on all SR top links with MN's, N15's, V's and any multitude of pre-grouping express locos.
However my personal favourite will be a three car set behind Hornby's forthcoming T9 somewhere west of Exeter.