Cheers, I tried the nakamichi 4mm banana plug but the flare type was too large for the Wiim ground hole (perhaps the nakamichi plugs are slightly oversized?) - there was no way it was going in see pic #1, so I bodged it an hour ago by removing one flare as shown below pic #2 and sent mum over with it for my mate to try and it now fits perfectly, its snug but can be inserted and removed without issues so mum is heading back over with the Wii phono lead and I'll connect it up using the nakamichi grub screws and send mum back over with it
EDIT - just heard from a post on another forum that a few folk have measured the plug at between 3.7mm to 3.8mm when compressed
It'd make my life (and everyone else's I imagine) so f-kin easier if I didn't have spms and could move around/do stuff myself.

, I can still do a decent bodge job though