My original post, obviously causing confusion here, probably needs explaining here, an the best way to do it is split it into parts.
1) IFR flight in class 'G' airspace
legally requires no navaids at all. The ANO only stipulates equipment requirements for IFR flight
inside Controlled Airspace
2) Flight on top is, in reality, VFR flight (provided you remain the correct vertical distance from cloud)
Therefore, you can fly on top, with no navaid equipment on board the aircraft. The fact that you happen to have one or two non-FM immune VOR receivers on board, which you know to be accurate, and can therefore help and facilitate your navigation, is neither here and there to the authorities, but a godsend to you.
Come descent time your options are as follows:
1) Descent to MSA - self calculated
2) Descent to lowest Radar Vectoring Altitude - provided by LARS
3) SRA to an airfield
4) NDB approach
Non-FM immunity does not preclude using an IMC rating. You just have to make sure you know the rules
