just to add my view of some people sitting in reserved setting!
i had a problem on the 09:21 to london paddington from taunton (first great western) on the 5th of december i got on the train and went to my seat and a businessman was sitting there.
so i asked him to move but he said he had a ticket for that seat and showed his ticket i looked at it and it was for another train so i explained this to him this but he refused to move but by this time the train was moving so their was two seats next to it free so sat myself there.
so to sort it out i took walk along to the train to see the train manager and he came back to me and he checked the man's ticket and he said he was on the wrong train but get this he was allowed to sit in that sit all the way to paddington as we had found two free seats!
i thought that with advance tickets you are told only to sit in the ones you are allocated on your ticket?
so to sum this up i found the train manager did not seam to do his job and the man very arrogant
old thumper