There is no easy way to do that... Either get a lower seat or remove those mounting points and install new lower ones (welding required)
1999 Volvo S80 T6 Quiet long distance cruiser.
1990 Volvo 360 GLi Waiting inspiration.
1989 Toyota Land Cruiser For days when wellies aren't enough inside the car.
1987 Volvo 360 GLi Being restored.
1986 Volvo 740 Turbo Sold, but not forgotten.