MIHC
The UK CAA had/has an AD whereby the starter circuit has to be either through a seperate switch or have an indication when the starter is operating.
The Islander has the External power switch to confuse pilots but it is common to see lights added to Cherokees. A Starter Operating lamp.
The placard you speak of is new to me but could be a CASA AD or other certification requirement. Some of those things can take a while to rewrite or sort out.
Often the original incident that prompted the requirement was years ago... but so catastrophic that no-one is prepared to change back from the status quo.
Has anyone put it to CASA ?