how strict are they about the size of your hand luggage these days (UK flights)? A couple of years ago they didn't bother solong as you could lift it into the locker yourself, btu the website now has a size limit of 55 x 40 x 20 whcih is pretty small.
Have theri policies changed since the new charge for hold luggage [cynical]?
Size limit is fairly strict & is the same for all airlines.
On easyjet though there is no weight limit (it's 5 or 10 kg on most) so if you have anything small & heavy but not liquid you can cram it in your hand luggage.
(Last time we flew lots of people had small wheeled suitcases which were presumably exactly the right size & you could get a lot in there - remember though you can still only have ONE item so if you have a handbag it'll have to go inside the other bag for the journey)