Clay has arranged music for: Keepsake, PLATINUM, FRED, Four Voices, Riptide, Backbeat, Marquis, Nightlife, BSQ, Max Q, Bank Street, State Line Grocery, Overture, Sound Standard, Svelte Brothers, and many other internationally renowned groups.
A stage adaptation of Softley's film Backbeat was performed at the Duke of York's Theatre, London (17 September – 24 March 2011), co-written with Stephen Jeffreys, musical direction by Paul Stacey, and directed by David Leveaux.
BBC Music made comparisons with the music of My Chemical Romance and stated that the song consisted of "double-speed punk backbeat, the apocalyptic end-of-all-things lyrics, the massive terrace chant chorus, the strange effect on the vocals and the general air of churning turmoil".
McDonald's stage debut came in 2010, playing the role of Klaus Voormann in the original stage adaptation of Backbeat.
Like Blondie's earlier single, "Hanging on the Telephone", the drumming pattern of "Sunday Girl" employs a double backbeat rhythm.