balus wrote on Jan 15^th, 2017 at 12:16am:

Have you tried re calibrating the joystick?

Yes. Numerous times, but it doesn't fix the issue. So either my joystick is a bit broken, or my USB drivers aren't working correctly.

I really need to do a repair of Windows 7 to make sure it isn't the drivers, as it seems to have started after I upgraded my computer a couple of months ago, but I'm being lazy!  :-[