Crab: The RN haven't converted to procedural because there is no requirement for it. If there was, they would have either absolved themselves of any civilian related SAR because of refusals by ATC to enter CAS or converted their cabs to comply with the requirements. The fact is (and remains) that a SAR cab will be allowed access thru Class D and thru A (occasionally) because it is a medical emergency. They have never been refused over the last 40 yrs.
Secondly, you can't do a procedural approach to a hospital, so you fly to the nearest LZ and transfer the patient by road - so the procedural won't help there.
Thirdly, you can use an ILS (provided it is left on overnight) without an IR under SVFR/VFR conditions anyway.
The proof of the pudding is with the Navy - you don't need a procedural to do mil SAR. (SH as you mentioned earlier is another subject and should not be mitigation to defend PIR in SAR).