Hi Barry,
Yes, it's called 'Mr Magoo's Invisible Wonder'.... There is NO cartridge inside the headshell, daftee!!
It was fitted purely for photographic effect, dude. There is a shadow, however, which looks like something is attached to the headshell.
Great day at Martin's, as usual. What a wonderful system he has!

Very educational, as usual, too... Boy did we discover some stuff to report on, but later - too knackered now to type much!
Martin, many thanks again for your excellent hospitality (and superb sarnies)
Laters,
Marco.