If you think that you have a BB speed problem, then to check the speeds coming in to your Hub properly, and whether they match what you should be getting, you cannot rely on wifi tests, - no BB supplier guarantees those - only speeds "TO" the Hub are guaranteed.
So, can you test speeds directly like this. As you expect >100Mbps then connect a 1GB enabled computer/laptop, with up to date drivers, via a known good and working Cat5e (Cat5 or a faulty cable will default to ~100) ethernet cable, directly into the Hub which you have put into “modem mode”. Test at speedtest.net (not the App!) to your nearest VM server - try on 2 different browsers.
If they are still low – boot the device into safe+networking mode and try again.
There are many posts on here where unknown software, corrupted browsers or other connected devices are limiting speeds on tests.
Report back what that gets.
-------------------- John --------------------
I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router +2 Airport Express's. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.