OK, so it's a desktop I'm using, so taking it elsewhere isn't much of an option. I have installed a wifi adapter to try using an internet connection through my iphone as an alternative. On the first attempt I was able to get the installer passed the point at which it would fail up to now. 100% of the download would run then I'd get a 'cannot download component IXEG...' message. Second attempt failed with the same error. If I 'ignore' the message I'd be presented with 'ixeg problem running post-install step. installation may not complete correctly' with a zip file location stating the location didn't exist.
So now I've tried two separate internet connections, with and without security, wired and wifi, running as administrator and not as administrator. I've been able to reach 100% download/install, but still unable to complete successfully.
What else haven't I tried? Is there anything else to try?