43 Inches, AIP GEN 1.5 para 8.5.5.4 see table and Notes 3 and 4
This reference is to do with nav-aid requirments and has nothing to do with the statement made in ENR-1.10 1.2.1. ENR-1.10 1.2.1 refers solely to whether an instrument approach exists at the destination and if you need a TAF, not whether you can use it to satisfy your navaid requirement or compare forecast minima to the charted value.
What this means is that if you do not have the relevent approved GPS reciever your destination becomes a "no-aid" destination, not a "no procedure" destination. You can still go to the destination and conduct a GPS approach but can not use the system to satisfy nav-aid alternate requirements.