I invested in 2 of the medium foldaways here Helen because they are the exact size for Ryanair.
http://www.flylite.uk.com/ Not particularly cheap at £20 but they are very strong and sturdy and a good investment . Only problem is No wheels and as you can get so much in them a strong man is required .:rofl
When we do our weekend breaks now I take a wheel along cabin case that I get hardly anything in and all the rest Daves clothes , extra shoes , 2 bags of toiletries , snacks etc Dave carries in one of these . No need then for you to pay and check in luggage for your weekend breaks either .