Joe,
Thanks for the reply.
The BIOS is completely up to date (one of the first things I checked), and as it is an Acer system there is no whitelisting in place. Plus in the case of both BIOS and fundamental hardware operation and compatibility, the fact that under the Ubuntu LiveCD the card worked fully straight away eliminates both as root causes.
From the testing, the issue is strictly down to the Windows drivers. Initially as I said using my existing Windows7 installation, the problem was that the drivers could not be bound to the hardware. So what I did was to completely wipe and reinstall the Windows environment from scratch, with the Intel card drivers the very first thing to be put back on. In doing so the card was then correctly bound to the driver and the first three manual diagnostics tests passed. However the card was still not able to actually see (and therefor connect to) any wifi network at all, on either 2.4GHz or 5GHz frequency. This was with the netbook sitting literally on the same desk as the wifi router, a distance between them of approximately 4 inches.
I also have to notify you that to try and confirm I had the full and correct drivers I did try to use the automatic check/update page on the Intel website, but that just caused either my machine to lock-up with a completely corrupted screen (if tried under Chrome) or a blue-screen-of-death crash (if tried under IE). So for my AMD C-50 based system at least that page is totally unusable.
In the end as the Windows 7 drivers are not usable at all, I have switched back to the previous Broadcom 802.11n card (which after the Windows 7 reinstall works perfectly, albeit more slowly than the 802.11ac card did under Linux) and I have returned the Intel card to my supplier and received a full refund. From some separate support discussions with other Acer users on their support forums I now hear reports from other users as well about issues and incompatibilities with the Intel Windows driver software, so I am fully confident that those are the root cause. And sadly due to this when I again look for an 802.11ac card in the near future, it will either be a Qualcomm/Atheros or a Broadcom model.