Is there an Advance available for your outward journey? If there is perhaps you could book that and then refund the whole off peak return.
It's not clear that there's a codified right to a refund of 50% of a return in these circumstances. There is a clear right to a refund if the difference between what you paid and what you used however.
There isn't anything in the NRCoT or PRO which explicitly sets out the method of calculation.
Obviously the retailer may argue it is just the difference between the return and the cost of a single, but that may well be a derisory sum and you could quite reasonably argue that you would not have agreed to buy a single if that had been the price on offer. Indeed, it might have been considerably cheaper to buy just an Advance.
I expect the coach is cheaper either way, but if not, and there is no provision of rail or rail replacement services by the TOC, you do ultimately still have the alternative option of exercising your right to be re-routed to your destination by alternative transport. Which, in as many words, means that if the TOC refused to rebook you on a coach etc., you could rebook yourself and then reclaim the cost of doing so.
Thank you both.
The journey is Glasgow QS to Oban.
There are unfortunately no advances available any more.
Annoyingly I could have bought very cheap ones when they first went on sale but wasn't totally sure whether we were going to want the first or second service out of QS as I wanted to possibly do something quickly in Glasgow just after the first departure so bought the Off-Peak returns.
Ironically I booked us on the second train out for the purposes of buying the ticket and when I went this morning to check the arrival time I found out it's not actually running, cut in ScotRail's temporary timetable so unless we want to wait until after noon, we will have to get the first train which I am worried will be rammed.
(It's not great that LNER who I bought the tickets through are still showing the cancelled train as being my departure on the app.
I would never have known if I hadn't checked for another reason altogether this morning).
Scottish Citylink have tkts just now for £11.20 each to return.
The whole journey would be cheaper and around the same length with them but I've never done the Oban branch so wanted to do the train. (Also we are coming up on the Sleeper that morning so was easier and safer in case of delays to do the whole journey by rail).