Thank you to all who replied. The people in the BA forum are so helpful! Thankfully, BA has made available seats on the 10:55 flight from MAN to LHR, which I promptly booked. It is hard to believe that even the low-cost carriers are asking $400 for their flights on the 30th. EI has lowered its cheapest fare to a bargain of $318. I could understand if the flights were full, but they do not seem to be.