Thank you all, just signed up to SeatSpy and already think it's going to be a good investment. Am having a play around now as we have a little leeway on dates before the schools go back, but I'm not convinced that 2 teenagers are going to be enthralled by a trip to Glasgow - somewhere with a beach was more what I had in mind, and I'll save the culture for when it's just me and Mrs RC...
IBZ possibly, although blowing extra Avios on CE wouldn't be my first choice. Could be my only choice though!