WIP Slow Ring updates won't install

[Steven Jepson]

Hey all.
First the basics - HP Envy 360, Windows 10 Home 64-bit, Windows Insider Program, Slow Ring (just moved there recently).

I've got an update (10.0.117738.1000 (RS5_RELEASE) that has been downloaded and is awaiting install, but it won't update. Every time I boot up, Windows Update says "Ready to Install - restart required", and on/off gives me the option "Update and Shut Down" or Undate and Restart." I've contacted MS twice, and they tell me it's an issue with the Insider Program and they can't handle it.

Any ideas here?

Thanks!