Okay, with the help of
@Radegast74 I found where to upload my DXdiag file... I had previously done this years back with an old computer so the data they had for me was different to the PC I am using now...
Telemetry now works for me. Either this fixed it for me,
or they fixed telemetry overnight (I didn't check before uploading my DXdiag file) is telemetry working for everyone now?
EDIT - I just uploaded the DX file from my shiposting laptop and Telemetry is still working, so looks like they just fixed it overnight
Nobody will be surprised to hear that my machine is sat on the purple dot of Minimum Spec, which is just fine for me :)