You're confusing FTTPoD with GEA FTTP unfortunately.
Make sure you have turned off "Smart Set Up" on the Homehub. See link how to do that.
You could also try giving the 2.4Ghz and 5Ghz frequencies different SSids. Just add a 5 to the end of the 5Ghz SSid so you know which is which. Check the 5 GHz Sync with 2.4 GHz: is set to NO.
Once you have done that "forget" the connection on your devices and then restart them and log onto both SSids.
See this link
You could try downloading and running inSSider. This will show you the wireless channels that your Homehub/router is transmitting on as well as the surrounding networks. You want to take a note of the channels in use and change your Homehub onto a channel that is not being used. Channel 13 is often the least congested on the 2.4Ghz. The 5 Ghz is not so congested so you could leave it on "Smart Wireless"
See Link how to do that.
See link for inSSIDer. Use the free version.
The 2.4 and 5GHz channels both have different SSID names already. Smart Set up on my HH5 was already off. Wirelss speeds on both of them are near enough the same.
This is the channel set up around here. I am on Channel 11 at the top.
I've no other electrical devices set up near my Hub.