Welcome to the forums tonyjhall.
I'm not familiar with your Sony TAP20, but it seems to use Windows 8. And Windows 8 should automatically find any device connected via USB cable. Drivers for USB, even USB 3, are included in the operating system, so you won't find them as an outside download.
The first thing I would do is try the drive in another computer using your existing cable. If it doesn't work in a second computer, try a different USB cable.