Thanks All for the advice re. getting the rear standard to swing. I've tapped the levers gently (rubber mallet), still very stiff. I have the exploded 'manual' showing the parts details so I'll get to work getting in there and cleaning.
If I may ask another question (I don't know if it's perhaps also related to the sticky rear swing). I've noticed there's a bit of vertical play where the 'L-brackets' that carry the rear standard along the geared focusing tracks meet the groove along the outside edge of the focusing track, thus allowing the standard to rock a bit back and forth. It's unaffected by locking down the rear focus knob. Admittedly, it's not much play, doesn't effect the ability to focus or image quality as everything is stable after the film holder has been inserted, etc. Could it be a problem (windy conditions, say)? Sorry if I haven't described what I'm seeing/hearing very well, but wondering if this is normal?
BTW, mine also came with a 5x7 reducing back and a half dark slide for making 2 4x10 exposures on a single sheet of 8x10, which I'm very curious to try soon.