Answer
Each passenger is usually permitted one standard piece of hand baggage to a maximum size limit of 55x40x20cm. There is no weight restriction, within reasonable limits - i.e. a passenger must be able to place the piece of luggage safely in the overhead storage bins without assistance. In addition, passengers may carry onboard a handbag, clutchbag, coats, umbrellas, duty-free goods, laptop computers, and small items of camera equipment.
Thanks for posting that. That was what I meant about no weight restriction - I was referring to the carry-ons. Nevertheless, EasyJet did weigh the carry-ons and seemed to be looking at the 10 kg limit. They did not measure them, and I was a bit concerned about being 1 cm over, but that didn't matter ultimately.