Q: Retina support update stalls

I'm having trouble downloading what sounds like a great update through "Apple Software Update", in Windows 10. The specific update name is "Apple Boot Camp Update, Version 6.0, Size 265.99mb"

I'm currently running Bootcamp 6.0, so I guess this must be a patch, The update summary says it will "Provide 5k support when running Windows via Bootcamp on iMac Retina 5k displays and address an issue that may prevent certain Macs from waking after sleep"... Which I need on both counts. However, the update never completes downloading, it hangs midway through the download and after an hour or two says the update has an invalid signature and won't install (presumably because it never finished downloading).

So far I've tried

- Running the Software Update utility with admin privileges,

- the download only option in Software Update,

- Re-downloading windows software from the boot camp utility in OSX, and re-installing the boot camp drivers, which only gets me back to where I am.

Does anybody have a solution to this issue? Is there a direct download link for the patch somewhere?

Cheers