It was actually a sewing machine bag bought from Lidl’s. It was just the right size, and ideal for popping an IPad, phone and even a small handbag in, which I can then use when I arrive.
I took a bag to Belfast and back a month ago, putting it under the seat in front of me. It was a shoulder bag, not one with wheels, but perfectly adequate for a weekend. I’ve flown with Easy Jet loads of times and had no problems.