How exactly have you managed to get a permit for a .45 caliber category H firearm as a school teacher? it seems like you must certainly fall within a small minority of Australian citizens.
Mine is actually a .38 and I got a permit by applying for it, filling out the forms, and sitting an interview.
The difficulty involved is commonly exaggerated by certain people. I wouldn’t call it easy exactly to get a Category H (and I have a Category C as well) but it isn’t really that hard. Getting my heavy vehicle licence was harder.