G'Day CS,
As I understand it, RH, being radalt indicated height, isn't what you would base your missed approach decision on unless it was specified that way on the chart, and I haven't seen that used in Australia.
The thing I would use as a cue to initiate a missed approach if not visual would be arrival at the pressure altitude nominated as the DH in bold on the chart, and use the RADALT by setting the low bug to HAT and cross checking on the way down.
That passage referring to RH in ENR sounds like one of those general all-encompassing statements they like to use, which can lead to a bit of confusion!
For a non-precision approach, RH will vary with the terrain for a constant run-in at MDA. We used to set it at the appropriate obstacle clearance height on a non-precision approach, again as a guide, ie 400 ft for Cat B.
Others may do differently, I guess, but as I see it, RH shouldn't be used for decision making purposes (unless of course it indicates a gross error from what you expected to see, taking into account the terrain on final).
Cheers