Where can I find a timetable for this service - I want to use it this summer.
Well if you go to Table 136 of the NR online timetable the stations on the line appear, but there are no trains shown between Yeoford and Okehampton, even on the summer Sundays when they are supposed to be running.
If you go to Traveline SW and select a journey by rail from Exeter to Okehampton on Sunday 3rd June the times do appear (dep 09:04, 11:03, 13:06, 15:06 from Central, etc.), but if you click on "timetable" it takes you to the NR timetable, as above.