I have just called the Caledonian Sleeper to ask to reserve a seat on my forthcoming journey from Crianlarich to Fort William. I have a Glasgow to Fort William Off Peak Day Return to use on my journey. I called because it says this on their website: https://www.sleeper.scot/tickets/seats/ Obviously there are no rooms available so that's not relevant. But I am told I can travel if I contact the Guest Services Centre to reserve a seat (Caledonian Sleeper choose not to allow this to be done online it seems). However, on the phone I was told that a seat couldn't be reserved for me, and that I would need to ask ScotRail. I expressed surprise at that, and it was explained to me that the Caledonian Sleeper service is 'divided into two parts' and is just a 'normal daytime train' on that part of the route. This seemed sensible enough, but I questioned what ScotRail had to do with it. The telephone advisor asked what company my ticket was for. I explained that I'd just booked a return from Glasgow to Fort William and it had no specific company written on it. They said that they would accept this ticket but that they could not give me a reservation. I asked if ScotRail could give me a reservation and they said that they did not know. I was a bit perplexed at this, so I asked why they couldn't allow me to get a reservation on their train when their website suggests that they can do that. They simply said that they couldn't offer one but that the train was a 'daytime train' which meant they would allow me to board. I asked them to clarify that this meant that I would be permitted to board even without a seat reservation, and to stand if there were no seats available. They said that boarding was subject to the availability of seats. Where exactly does this leave me? No alternative trains are available, because the train is 0746 from Crianlarich to Fort William, and the next is more than 3 hours later and would not be suitable for me.