Broken stacking chairs / repairable with right tools (Loftus Road W12)

12 Dark red upholstered hall chairs left over from a recent chair audit at our community centre. Photos show broken seat pads or back rests. With strong glue back rests can be slid back and secured. Seat pads on done of them need hammering back into position on their grips . Would rather all went at once but CV like separate into 2 x 6 if needed. Too heavy to collect without a car. All of them need an upholstery clean .