Yes, they can get up and scoot when the need arises. The Nottingham is slightly different hull construction. They also have an offering around 60 inches long. The company web site is:
Nottingham They are the official source of class legal (48") CJ hulls in the UK. The American source is a Mr Hans Berger and his contact info and prices can be found here:
Hans Berger Hans is a great guy and will deliver to you anything from a bare hull to a turn key boat. Like everything, it just takes money.
The class was actually started in Australia an is quite popular down there. In the US the largest collections are found of course on the west coast. But there's a couple of groups in Texas and more smaller groups and individuals popping up all over.