I have an Off Peak Return from Marden to Blaenau Ffestiniog.
The normal route would be to travel via Llandudno Junction.
Can anybody advise if I would be permitted to break my journey at Llandudno station on the return leg please?
Break of journey is permitted on the return portion of that ticket - unusually for a walk-up ticket, it's not permitted on the outward portion*.
However, the double-back between Llandudno Jn (LLJ) and Llandudno (LLD) isn't on one of the many permitted routes between Blaenau Ffestiniog and Marden. So the question of break of journey is moot, as you can't go that way anyway (with or without a break of journey).
As
@jfollows says, adding on a LLJ-LLD return is the way to go and this is very inexpensive at £3.40 for an adult-rate Anytime Day Return.
*Essentially this is because Avanti-priced Off-Peak tickets between/via London and Welsh stations have less onerous time restrictions than those to English stations (south of Lancaster). Accordingly, they don't want it to be permitted to use an Off-Peak ticket to/from Wales just for travel within England.
