@jonnypencils I just found a blog post by @olimex which I already searched for when I read your toot for the first time, but did not find back then. Maybe this is also relevant in your case since the #WiModem is also based on the #ESP8266 (AFAIK).

https://olimex.wordpress.com/2021/12/10/avoid-wifi-channel-12-13-14-when-working-with-esp-devices/