After un-installing, removing the registry, then using the MSI to install manually that worked.
However on a completely new site with another server 2008 R2, i have IDENTICAL issue, however this one i wont get away with rebooting loads of times....
Theres definitely an issue with the one click installer somewhere...
The root issue seems to be the Host service not starting. That, in turn, may be caused by different reasons but often this is due to either security settings or antivirus software activity.
Not sure why it happens in this case though. We'll do additional testing on Windows Server R2 to see if we can reproduce the issue.