Hello folks - I thought I was selling the Madrid change well but ultimately it was in vain.
So top marks for the alternative date suggestions; as it was a Friday we have decided to find a hotel in Mahon on the Friday and come back on the 17:00 on the Saturday.
I've booked 1A and 1C on the outbound leg and the return aircraft has an emergency row with just two seats in it so we have selected them.
Thanks as ever.