There is no "2 out of 3 rule" - it's a myth of airport bars.
CAA licence, in UK, N registered a/c
OK - reference: FAR 61.3
CAA licence, in US, N registered a/c
Not OK - ref as above, an N-reg must be flown under a license issued by the country of the airspace, or by the FAA
FAA licence, in UK, G registered a/c
OK - reference UK ANO article 26 - a G-reg can be flown worldwide, OCAS, on any ICAO PPL.