Hi all was trying to find info on this but couldn't find any well i have worked it all out so i will share.
If you need to take the height adjustment off take note it is under tension if the seat is in the down position ,so you need to sit on the seat raise it to full height you can now remove the ratchet handle (not under tension ) if yours is broken it will be the ratchet either the large sprocket strips in one section or the lever if the sprocket strip you can rotate it so the damage is in a spot not used and it will work again. Never release the lever without sitting on the seat .