My CS which I believe to be a december 1946 model (CS56022) has a brass plate riveted to the rear of the cylinder which states .....the cylinder is 10 thou oversize.... so I assume that at some point the cylinder was removed and sent to lister who did the work and returned it with a new oversize piston, from what I know the engine was probably worked hard for the first twenty years of its life and I know personally that it has not been punished during the last thirty years, anyway has anyone else got a CS that has been returned to lister workshops for servicing/repair that was returned to the owner with a workshop brass plate riveted to the unit