Theatre includes: City of Angels (Garrick Theatre), The Antipodes (The National), The Deep Blue Sea (Chichester Festival Theatre), Young Frankenstein (Garrick Theatre), Saint Joan, City of Angels, Coriolanus, The Vote (all Donmar Warehouse), Long Day’s Journey into Night (Bristol Old Vic), The Winter’s Tale & Harlequinade (Kenneth Branagh Theatre Company at the Garrick Theatre), The Machine (Manchester International Festival & Park Avenue Armoury, NYC), The Pajama Game (Chichester Festival Theatre), Les Miserables (Queens & Palace Theatres), The Pirate Queen (Broadway), The Fantasticks (Duchess Theatre), A Christmas Carol (Birmingham Rep), The Shaughraun (Abbey Theatre, Dublin), Assassins (Sheffield Crucible), Pacific Overtures (Leicester Haymarket), Longitude (Greenwich), The Pirates of Penzance, Peter Pan (both Savoy Theatre), The Far Pavillions (Shaftesbury Theatre), Putting It Together (Harrogate Theatre), The Last 5 Years (Theater Aspen, Colorado) and The Phantom of the Opera 25th Anniversary (Royal Albert Hall), Les Miserables 25th Anniversary (O2 Arena).

Film & Television includes: All Is True, Murder on the Orient Express, The Legend of Tarzan, Les Miserables, The Lost Tribe, Decline & Fall, The Wrong Mans, Endeavour, Holby City, Doctor Who, Pompidou, Him, Sons of Liberty.

Hadley wrote the book and lyrics for the musical Committee for the Donmar Warehouse and is a Fellow of the Royal Academy of Music.