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We have already bought, paid for and received the tickets, it was just the seat reservations that was the issue. Dzug2, you are quite right in saying that we have flexible open tickets and I can see your point now about the cheaper advance tickets As we have previously booked a ticket in advance and then checked the prices again as someone else was going to accompany them and the prices had increased considerably, so this is why we have booked in advance plus they wanted to book accommodation and needed to make sure that they had travel arrangements in place at the same time, however the cheapest tickets at the time were the flexible open tickets. We are new to this train travel malarky and so are still learning the ropes - I think we have got it right this time as they want to be flexible with their travelling around. I can also now see the booking horizon date on FGW website, it just didn't make it clear to newbie travellers what this date meant ;) thanks to everyone.for all your help.