Green’s Dictionary of Slang

(UK teen) good, excellent.

1974		Adamson & Hanford Zimmer’s Essay 70: You think they were really something, don’t you? Really tough, really animal.
2001		Guardian G2 3 Aug. 3: They was [...] the nuts, animal, mad, cracker.
2002		O’Byrne Files: Dublin Sl. Dict. 🌐 Animal, adj. Wild, uncontrollable, exciting.