Update note.
Although these are advertised as available from ticket machines they are not, and won't be - they can only be bought from a ticket office, or on the train.
If boarding at St James Park - the promo has not been loaded from this station on to Avantix▸ ; the guard needs to manually enter the 50% discount.
There is no time restriction with the exception that return travel is not permitted on the 07.00 departure from Barnstaple. The promo is valid all day.
Thanks for this. Just a PS - while there is not a time restriction from Exeter St Davids and Central, there is a time restriction from Topsham, Digby & Sowton, Polsloe Bridge and St James Park. The first train people can catch is the 08 52 Exmouth - Barnstaple on weekdays.