My advice is try someone other than O'Brien.
I had similar troubles with my KE25 windscreen, the quotes that I got are below, and in the end the only one that didn't ring back an hour after the quote saying that their supplier didn't have the glass was Auto Glass. They may be able to help you also, their number is (03) 9562 9088.
Auto Glass - $195
National Windscreens - $245
Instant Windscreens - $300
O'Brien Windscreens - $380
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