Clarks has 30% off if you complete a survey to get what clearly is not a unique code. I've done the survey so you don't have to.
Postage is $9.95 or free for orders over $99.
Maybe get your kid some sweet gumboots for $15 - 30% + postage: https://www.clarks.com.au/girls/gumboots.html
Or some $500 desert boots for only $350 - https://www.clarks.com.au/desertboot-3-mens-37024.html - no I don't know why they are so expensive.
T&Cs: 30% Off your next purchase available Online Only upon completion of the survey. Offer valid Thursday 21 June - Friday 6 July 2018. Offer excludes prior purchases. Cannot be used in conjunction with any other offer. Discount applied at checkout when you enter the unique code received at the end of the survey.