What do 'backup checks' amount to anyway? Do they involve checking on whether the purchaser and everyone in their household is completely trustworthy? Do they involve checking that their are adequate storage facilities where the weapons and amo will be kept locked up?   Or are they just does this guy have a criminal record and have they ever been sectioned?

A right to bear arms, however interpreted, is not the same as a right to sell arms or buy them without the most stringent requirements seen as appropriate.