Chris
Thanks indeed for the example you give of , I assume, Set 61 replacing 60. I comprehend the process now. Yesterday, I joined Robert Carroll's coaching group on Yahoo and found the Plymouth area coach workings for 1962. It seems that at that point, 3 sets serviced the branch: 58, 59 and 61. One would be the Wednesday swap-in.
Do you believe that the replaced set remained at Newquay until the next Wednesday exchange?
Also, a bracketed note under Set 58 reads: "Set No. 59 previous day". I know the branch locos alternated duties daily. Did the sets - and therefore their coaches - also alternate workings and set numbers at the end of each day?
Cheers
Brendan