Bluetooth issue after Windows 10 anniversary update

I have a Logitech Bluetooth keyboard (K810) and mouse (M535), along with some other Bluetooth devices such as a couple of speakers. This is all used with my 2015 Dell XPS laptop, and worked perfectly fine.

The Windows 10 anniversary update was installed, and since then I have had Bluetooth issues.

Basically what happens is all of a sudden all Bluetooth devices completely stop working. This can be while idle, or when using the machine (ie. typing using the BT keyboard). The mouse and keyboard of the laptop work fine still, just the BT devices do not work.

Looking into the Windows Bluetooth program, I can see the devices still detected. I can turn off/on the devices on the actual device, or even within the Windows Bluetooth program. No joy. I can even turn Bluetooth off/on on the PC, and still nothing, even though the devices will show up.

If I reboot at this point then it all works again fine once back up. This happens at most once a day, but normally once a week or so. And only since the Windows 10 anniversary update. Never ever happened before.

I've done all driver updates Dell listed, plus queried the MS forums (they said come here).

Any one else have the same issue, or have an idea how to fix?

Cheers