Green’s Dictionary of Slang

absolutely perfect; also as excl.

1998		S. Sinykin Heather, Belle Of The Ball 12: ‘Perfectamundo!’ Megan’s green eyes lit up at the suggestion.
2000		Guardian 14 Jan. 32: No dear, seriously, you’re perfectomondo as you are.
2006		auntienoo.blogspot.com 14 Dec. [blog] Perfectamundo! Well, what can I say? The Panto was FAB!!!!