Australian cost sharing makes Sydney politically plausible

Treaty geography and physical geography cannot be changed without breaking the scenario, so the key lever is who pays. If Australia bankrolls the docks and supporting infrastructure while Britain supplies personnel, even cost-conscious ministers gain a reason to accept Sydney. Advocates of a Far East base still obtain one without disrupting the treaty system. A joint base with the Royal Australian Navy inside Australia is also harder for Japan to portray as a provocative forward move. The result is strategically inferior in location but politically attractive because much of its immediate bill falls outside the British Treasury.