Agents at EDI were, as always, extremely helpful.

They offloaded me from the EDI-LHR tonight and then moved my EDI-LHR flight that I was going to no show for back to my original flight this evening (does that make sense?). So I am travelling to LHR this evening on the original booking but all they have done is moved the first flight forward to tonight and no showers me for the separate EDI-LHR booking I made. Have my boarding passes printed for subsequent sectors as I watched the agent essentially rebuild all remaining sectors on the booking and check me in.

One thing worth noting is that he said regardless of ticket type booked in Business, the airport has complete flexibility to change anything about the booking should they so wish as if it were a completely flexible fare. That is how they were able to move my initial flight EDI-LHR to tonight even though I had booked an I class fare.