The recording was further delayed when lead singer Roger Daltrey underwent throat surgery, and when during a lengthy Christmas break, Townshend sliced his hand in a window during an argument with his parents. Former Zombies and Argent member Rod Argent was also called in to replace session keyboardist John "Rabbit" Bundrick after Bundrick suffered a broken arm falling out of a taxi at the studio door. When the sessions resumed in March, they were moved to RAK Studios, which caused further delays due to the equipment malfunctioning, including the wiping of a backing track. Astley stated that the RAK equipment made the existing material sound different when played back, necessitating further delays as he attempted to fix the audio problems. In one incident, Daltrey punched Johns in the face due to an argument over a rough mix, rendering him unconscious. The argument was fueled by Ted Astley adding a string arrangement to "Had Enough", which Daltrey derided as "slushy". After one long and frustrating day, Townshend planned to fire Moon from the band unless he cleaned up his act. The plan drove Moon to attempt to kick his alcohol habit and work more enthusiastically. Due to a prior commitment to produce the Joan Armatrading album "To the Limit", Johns had to leave in April, with Astley remaining as sole producer. Under Astley's command, the sessions returned to Ramport, with all of the drums except for "Who Are You" recorded in the last two weeks of production. "Who Are You" was released on 18 August 1978.