Survived the trip, looks like a late 70 with the full length scratch plate.  Fortunately the platter was on tight, one of these bouncing round inside the box can only be bad news.  A couple of sharp taps with a wood block served to free it, and reveal good news - metal idler wheel.

Take out the small screw in the bearing housing to allow the spindle to be removed - dry as a bone

The cone drive shaft also had some corrosion, easy to clean up with fine wet/dry paper.

Led Zeppelin II - a suitable period recording for the 70!  Sounds typically dynamic with low compliance Ortofon cartridge.

Later, looking for a bit more clarity I tried the Shure SC35C.  Very good match for the arm and a much more solid sound, perhaps the arm is a bit heavy for the Ortofon. 

This is the precursor to the best selling L75.  It has very similar dimensions, and fits an L75 cut board apart from needing a little more room around the start/stop switch. 

It has the heavy alloy platter, and large main bearing. 

The obvious difference from the 75 is the arm, which has much in common with the L59 arm.  It is a much more conventional arm than the L75, with pin pivoted bearings for vertical motion rather than the knife edges that cause so much trouble on the 75.  It is also longer than the 75 arm, with a spindle to pivot of approx 230mm.  It uses a similar mounting collar to the later L69/L72/B55, with a 14mm pillar.

The vtf adjustment is via a spring rather than sliding counterweight, and the scale goes to 15gms!  The headshell is rigid plastic and the fixing non standard, neither SME or L75.  :-(

I like this arm.  I mounted an Ortofon FF15 cartridge for the first test audition, and despite a plastic idler the sound was clear and detailed with excellent dynamics.