Thanks for the offer Dean, and Jim for the suggestions. I did actually find some grommets that I thought would work (they were designed to fit a 1/4" thick panel, and surprisingly, sourced here in Adelaide) but my main problem was that the holes in the bodywork were incorrectly positioned ....one was too far forward and the other was too far aft. Result was - no amount of available juggling would enable me to use the grommets without gaps showing. I hadn't wanted to use the supplied SS 'washers', but had to concede that their use was my only option. Even still, one washer-securing screw and nyloc out of three for each leg is hanging in the breeze (but you can't see it, and it doesn't matter). The end result is visually quite good - I'll take a pic of it tomorrow and post it here.
How is progress on your AP427? I hope my comment about 5-speed autos in another thread was taken in the manner it was offered
Cheers,
Glen