Morning IO540,
I am guessing that 91.1 and 91.703 are in there to make sure Chicago Convention stuff are put in the FARs. My understanding of these ICAO regs are that if you are flying in (for example) UK airspace in a US plane with a US pilot certificate, and there is any discrepancy/uncertainty in the regs, the more restrictive will apply.
So, its my interpretation (oh no, not another one!) that the FARS expressly prohibit an instrument letdown to a civil airport unless there is an approved IAP. The UK don't appear to have that restriction. Therefore if you are depending on an FAA certificate, the more restrictive reg applies, and you cannot do an instrument letdown in UK airspace if no CAA approved IAP exists.
If somebody else inteprets differently and wants to do so then that's up to them, but I would not expect the FAA to turn a blind eye if you hurt somebody and survived. So I would not do it without an IMCR, and even then my personal risk/reward calculation would prohibit it for me.
Bookworm,
I quoted 91.169(c)(2) to demonstrate that Class G is not a 'lawless zone' and regulations apply to IFR flight within that airspace and when letting down to an airport within.
cheers