Green’s Dictionary of Slang

excellent, wonderful, just right; often as the gear.

1962		Mersey Beat 20 Sept.–4 Oct. n.p.: The first time it was pretty rough, but we all had a geer time.
1964		M. Braun Love Me Do 79: ‘Oh, we like the Beatles. They’re gear’.
1968		‘Hy Lit’ Hy Lit’s Unbelievable Dict. of Hip Words 17: (it’s) gear – British expression for anything great, excellent, tough, boss, out-of-sight.
1971		T. Lewis Plender [ebook] ‘I do like your get-up, Mr Froy. I really do. Real gear stuff’.
1981		S. Berkoff Decadence in Decadence and Other Plays (1985) 19: How splendid spiffing whizzo fab and gear.
2004		P. Smith Two of Us 140: There was a Beatles-themed cruise to the Sea of Cortex in Mexico, even a Liverpool-based ‘fab, gear, groovy, cool, out-of-sight corporate teambuilding workshop.’.