Brilliant!
I never fail to be hugely impressed in how quickly one gets a response on this forum!
Yes Parapunter - I'm using both a Logitech Alto laptop keyboard (Brilliant piece of gear!) and a Logitech optical mouse ... suspect that the culprit is the latter because I don't remember loading a driver for the keyboard.
Will reload the mouse driver - when and as I get around to it!
Many thanks!