I am sorry to hear that have had issues updating the video drivers on your computer.
The problem may be that your computer manufacturer does not allow the installation of generic Intel video drives. You are required to install drivers from your computer manufacturer; however, you may try to force the installation of Intel generic drivers by performing manual procedure, see here for instructions:
Select your operating system version and download the zip version of the video driver:
Hi, thanks for the reply,
Sorry, I probably could have made this clearer: this was the procedure I'd been following having previously searched and found the instruction pages you offered above, with the system refusing both the ASUS-repackaged and Intel (generic) driver updates (both newer versions) insisting that all drivers were up to date.
I had already tried overcoming the "driver not authorized for this product" issue by accessing the graphics driver through the Device Manager console, and manually locating the downloaded .zip files, but this was again blocked at initial setup as Win8 insisted that all drivers were "up to date" already, apparently without even testing the version of the offered update packages...
Is it likely that this is an issue with ASUS' authorisation mechanism for their driver packages, in which case I should ask them?
Hmm, whole thing seems to have independently fixed itself now : P
But thanks for the help.