A big thank you to Jay Wardark and John Morpork for pointing this workaround out.
For ages I have thought my radio HUD was totally broken as it received no messages, but if you send out a message on it ( such as /91 "Dispatch, Ocean 7349, Radio check, over" ) then it magically springs to life and you will then receive incoming messages. Unfortunately you have to repeat the process after every crash.
As this bug is still stopping many from seeing messages I (and others) have taken to copying our transmissions into the HPD and Municipal Groups to where appropriate.
Hope this helps 🙂
Angel