I've used the connect app to help improve the signal, and I've checked the connections are tight. As I said it works fine for a day or so, when we get bad speeds, we cycle the power and usually everything is ok again. Could it be due to the number of devices connected to the hub? the connect software is currently reporting 18 devices connected and another 5 connected to the booster, that I fitted yesterday.
I've had similar issues with wi-fi over the last few months - and had little help or response from Virgin to be honest. Took the bull by the horns in the end - and though you can argue Virgin should not be giving out a router incapable of managing multiple devices on the 2,4/5Ghz ranges effectively - it can - but only for a limited number of devices it seems.
With Smart devices now seemingly filling up the bandwidth - my house was fine till I started adding these, Echo's smart switches, etc etc - I tested the response with a second router plugged into the Hub 3 and switched it to Modem only mode as my research suggested. Whilst this only had a 2,4Mhz band - the issue went away - due to the traffic issues that the Hub 3 seemingly cannot cope with.
With the issue resolved and wi-fi or rather Internet I should say not dropping all the time - I installed a Netgear Nighthawk the other day to give me the facilities everyone needs, proper traffic monitoring, better speed, stronger signal.
I too had tried the boosters after some bright spark from Virgin support had suggested I needed those. No difference. As I assumed at the time.
SO I would suggest you do the same - cough up for a decent Router, and get the Wi-fi you should have. I'm getting what I should have on the devices, and no dropouts any more.
Seems to me the Hub 3 can only manage about 10 devices effectively. Anymore and you're in a world of pain.
Might seem extreme - but the Hub 3 just isn't up to the job it seems.