Arse-about-face Definition

adjective
(idiomatic, UK, Australia, New Zealand) Placed or arranged the opposite way to the way it should be.
No wonder it doesn't look right mate, you've got the whole thing arse about face.
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Arranged in a confused or haphazard way; muddled.

Wiktionary
adverb

(UK, Australia) In a manner that is opposite to or the reverse of the way it should be, backwards.

Wiktionary

In a confused or haphazard manner.

Wiktionary