And they wonder why they get such a bad wrap! Blardy Scum Buckets! You pay good money for them to uphold their end of the "contract", just as they would if it was the other way around (and don't think they wouldn't).
Never settle for less than ... A: what you pay for B: what you deserve C: what you are lawfully entitled to ... even after the "repair".
You might be "just a number to them" but you certainly aren't stupid and tell them so! Do your homework and if they continue with this angle ... I'd also make it known that the underhanded way you were approached by their representative (insert the offenders name here) is offensive to you and if they continue treating you, their "valued customer" this way, you would seriously consider taking your insurance $ elsewhere (not a serious threat in their eyes) and telling all your friends (all 7000 or so of us) to do the same. Maybe throw the word "Ombudsman" in for good measure if you don't get better treatment.
Their repair warranty doesn't end when you give them the "flick" either ... it's a "lifetime warranty on repair" remember.
Do Bunnings have carpark security camera's? I'd be asking them so you can try to find the offender. They'd only need the date and approximate time and of course a description of your car and where it was in the carpark. If they don't ... who else around them does? You might just get lucky.
You'd probably still need to pay the excess up front, but once they have the offenders details, they will pursue them relentlessly, and you'd generally get your excess back after repair (I believe).
Kit_e