Bluetooth WiFi Conflict

Hello.
I have the C5J6 3G on Windows 8.1 (updated BIOS 2.02 & Lollipop V5)

The WiFi drops from 20 Mps to around 5 Mps when my Bluetooth keyboard is connected in Windows.

I've tried installing the drivers suggested & posted here, but they refuse to install. Can anyone tell me the correct way to install?

So far I've tried:
Right click > Install
DeviceMan > Update driver > Let me choose (which says not compatible will not install)
DeviceMan > Uninstall Bluetooth Radio (to which Windows just automatically reinstalls with the 2006 drivers!!)

Any help? Cheers...