Tyt dm-680 dmr radios

Has anyone any experience of these? I bought a couple to test with the intention of them being a similar radio to the TYT UV-380/390 but with a simple channel knob - ideal for an elderly chap with failing eyesight who just wants to chat on the local DMR repeaer. The snag is that the programming cable for the 380/390 which does not use the prolific chipset in the USB connector doesn’t work, so I assume this radio needs a ‘clever’ cable - but despite having lots of cables, I cannot get the radios to programme at all. The supplier had a few going quite cheaply, but doesn’t know anything about the cable? The CPS appears to be the right one from the data I see on screen, but I cannot download from the radio. I’m stumped and the radios are quite hard to get. There is also an MD-680d which has a LED through case simple display. Possibly the software is for the ‘d’ version, and the radio is NOT the ‘d’, but I don’t know?

EDIT - TYT just confirmed it needs the bog standard Kenwood style cable, which I have already tried, so the mystery deepens …