BT Homehub 4 Wireless connection issue

[#1]

I am connected to PlusNet fibre using an Openreach modem and BT Home Hub 4 router, most of the time without issue.
On occasion the devices which wirelessly use the 2.4ghz connection lose connectivity to the internet. This seems to happen only when a particular (neighbours?) SSID is visible. I have tried changing the channel selection from Automatic (Smart Wireless) to the best channel found using Wifi Analyser. When I do this, after applying the change I  cannot see my 2.4ghz SSID on any device (even if I reboot the router). I do not have any issue with the 5ghz connection.
Any ideas of the best way to resolve this please, right now I am thinking new router?

[#2]

Hi Razorback,
I'm not intimately familiar with the HH4 however it sounds like the channel selection may have led to perhaps only the higher frequency ranges of 5ghz being available.

[#3]

Have you by any chance changed to channel 13 or 14?
If you select channels 13 or 14 (valid in UK & Europe but not USA where only channels 1 to 12 are allowed) some equipment (using USA spec.) will no longer see the signal.

[#4]

I was trying to change to channel 6  which appeared the strongest