I was reading something this evening on Australia's Iroquois, what was particularly interesting was that initially the type was solely intended for search and rescue and army support was only added after the selection had been made and orders placed. At this time the army, while very keen to substantially grow their organic airpower, were limited (by legislation / policy / regulation?) to a maximum weight of aircraft permitted, effectively preventing the operation of utility helicopters let alone anything larger.
At the time the Iroquois was ordered the RAN was actually the most experienced rotary wing operator with the RAAF having almost no experience and the army having none. It is extremely fortunate that the RAAF decided to expand the intended missions of their new helicopters to include army support otherwise the ADF could have been left without any tactical air support at all.
Of interest is that the RAN initially selected the Wessex as their SAR type but following the decision to use the Wessex as an ASW platform the FAA acquired UH-1Bs and Cs for the SAR role instead. I wonder, in hindsight, if the RAAF should have retained the SAR role, maybe added CSAR and even SOF support, with a larger more capable type, while the army took control of the support and utility roles twenty five years earlier.