Yes Mac it was my Dell that gave me that message but the thing is that when it does give a message (it doesn't give one every time) it is correct for the situation i.e. it says capacity has increased when I plug the drive in and says capacity has decreased when I plug the thing out.
Unfortunately the laptops (not Dell) cannot see it either.
No BOAC, no sign of it in the hardware and all the drive letters ticked looking in TweakUi. The thing showed up without a problem as drive E: when I was formatting it.
When I plug it in now, the pointer arrow on the screen flickers a few times as the computer "looks" at it and the drive itself "whirrs" up no problem but that appears to be as far as it goes. Oh well..