128.9 seems to be where the microlight guys discuss the view
I think the cousins at Lakenheath might take a dim view of that. I think Mono means the microlight frequency 129.825 - but it is not for air to air chat (although lots of folk use it for that which seriously pi55es off everyone else).
The simple fact is that air to air "chat" is not allowed on any of the VHF airband frequencies.