No attenuator was fitted. I've checked all the connections at the wall box inside and at the hub and they're fine. The service status test says "We didn't find a fault with your equipment", no surprise there.
We had this symptom after Virgin first upgraded us to a Hub 3.0 but it seemed to settle down after a couple of months, I can't eremember what the signal strengths were back then.
If the tests can't spot this problem they're worthless.
Should be finding your issue then testing neighbours and going back into the network to establish extent of the problem, then raising a ticket for a service technician if just you or a network engineer to attend.