This is damn annoying. We downloaded a whole set of them and after a bit they all died so you have to download them again periodically.
Not a viable solution.
In the end we just set up an activated VM (using MSDN licenses) with RDP enabled for each config on a Win 8.1 HyperV machine that sits in the corner of the office.
I consider IE testing and support as an extra feature in all my projects, and am quite happy to bill an extra hour for setting waiting to download and setting up VMs.
Not a viable solution.
In the end we just set up an activated VM (using MSDN licenses) with RDP enabled for each config on a Win 8.1 HyperV machine that sits in the corner of the office.