Many thanks Joseph. Inevitably, the fault doesn't happen continually, and now I want it show up, so far it hasn't! I'm all set to get a screenshoot as soon as it does. To answer your other queries in...

I'm continuing to receive these warning messages when the extender is switched on. I'd really appreciate some help with this!

I set up this extender yesterday and it appeared to be working fine with a laptop and a smart TV. However our PC (uses ESET Security) reported that a device on the network was passing malicious...