Vauxhall Vivaro C Owner's Manual page 50

48 Seats, restraints
Longitudinal adjustment
Pull the handle, slide the seat, then
release the handle. Try to move the
seat back and forth to ensure that the
seat is locked in place.
Backrest inclination
Turn handwheel to adjust inclination.
Do not lean on the backrest while
adjusting.
Seat height
Lever pumping motion
up : seat higher
down : seat lower