For the avoidance of doubt, the text that Circuit Basher quotes is
not AWN 84. It is Aerocoms's interpretation of AWN 84. In particular:
If you fly with non FM immune equipment after 1st January 2001 in class A, B, or C airspace or under IFR/IMC conditions you will be breaking the law.
is flawed.
There is no requirement for the carriage of FM immune equipment (or
any particular radionavigation equipment) outside controlled airspace under IFR.