I travel long distances most days, and this just isn't true. I've seen many people forced to pay a surcharge because they booked to travel at a particular time, but actually travelled at a different time. If you have booked a ticket for a stated, timed train, then you must travel at that time, or your ticket will be worthless. I suggest you get down to teh station hotfoot and see if they will transfer your ticket to another train.
A surcharge? They were let off lightly - I was on a First Great Western over Easter (from London to the west country) when it turned out someone in my carriage had got on the train 30 minutes earlier than they were supposed to. When the guard spotted this, he immediately went and contacted the police who escorted said passenger off the train at Reading. Simple as that, no row or anything, just handed it straight to the BTP. Quite unbelievable (and the protests on his behalf by other passengers did nothing).