Guess who managed to score an original PowerBook G4 titanium battery in mint working condition with only 41 cycles on for just £10. An accidental miracle. Facebook market place to the rescue! :
NewerTech® : Batteries : Notebook Battery Charger and Conditioner for PowerBook G4 15-inch Aluminum
PowerBook G4 Aluminium 15" Apple Battery Original 661-4200 A1078 A1148 A1045
DK LABORATORIES
Rebuilding a PowerBook G4 Battery « Keith's Electronics Blog
Apple® PowerBook® G4 17 Inch Aftermarket Battery | Webdirect