An update on my situation, not sure if it will help everyone else or not.
Found a driver here: Intel HD Graphics 4400 Driver 10.18.10.3282 for Windows 8.1 64-bit Windows 8 driver download - Windows 8 Downloads
Device manager reports the driver date as 26/8/2013.
I uninstalled old driver (deleting driver files) and rebooted. This auto-installed the basic Microsoft driver. I then downloaded the above cab file, expanded the files into a new directory (command prompt "Expand src /F:* dst") and manually installed the driver by updating the driver on the basic driver from device manager and pointing to that folder.
That seems to have fixed all of my issues (although I've only been using it for an hour). I now have my 3 monitors working again (Targus USB 3.0 dock) and no visual studio crashes.
I'm also running the latest version of DisplayLink drivers 7.4M0 from here: http://www.displaylink.com/support/downloads.php
Hope that helps someone.