Thanks to those of you who read my earlier post. It's taken a while, but as of two days ago the motor plate is moving as it should. For nearly the whole of the almost four intervening weeks, the head plus motor assembly has been suspended, motor uppermost and (very heavy) head casting downwards, from webbing straps, so as to dangle an inch or so off the well padded floor in the hope that gravity would encourage movement. The bearing was been anointed periodically with penetrating oil. Softwood wedges were driven (gently) into the narrow gap between head casting and motor plate without apparent effect, other than the compression of the wedges.
Ultimately, movement was achieved on Sunday evening by applying quite modest leverage in opposing directions via a bar inserted between flanges on the motor housing and a big screwdriver inserted into the access hatch on the head casting.
I think the main ingredient in the end was time for the penetrating oil to do its stuff. So if it happens to your CL2, don't panic - not for a month anyway.
Now to learn how to use it!
