No Rob, the Residential qualification is separate from your Country of birth qualification. You can shoot back to back for different Countries if you have satisfied ONE OR MORE of the criteria.
"Once a competitor has represented a country in the Championship he/she may only change residential qualification after one year’s residence in the new country"
If you qualify one year using residential qualification, you can then choose birth status for the next year without standown. The standown applies; and is clearly stated, that to change RESIDENTIAL qualification there is a 1 year standown. It does not apply to birth or parental qualification.
Where Don managed to shoot for NZ in Italy he did so based upon Birth. He then shot in Norway based upon continuous residence in England of more than "at least one year". He could choose NZ again at any time, and the satisfaction of "ONE OR MORE" of the criteria allows him to do that.
Standown only applies to changes of residence. One does not even have to be a citizen to represent an RGB. Shooting for one's nation of birth satisfies one of the three criteria.