Original: The works included a major rebuilding of the great organ , originally built by '' Father '' Henry Willis , subsequently rebuilt by Harrison & Harrison and most recently rebuilt by Mander Organs ; The organ is now again the second largest pipe organ in the British Isles with 9,999 pipes ( Liverpool Cathedral has 10,268 ) .
Simplified: It was built by an organ maker called Henry Willis and was later rebuilt by Harrison & Harrison and most recently by Mander Organs ; It is the biggest organ in the British Isles with 9,997 pipes .