The seat cushion on my Spacesaver seat is stuck. What should I do?

At times the cushion release valve mechanism of the seat cushion appears to no longer work or feels stuck, refusing to allow you to release the seat cushion to change its position.
This doesn't necessarily mean the valve is faulty, it may simply be solved by returning the seat back to its resting position using the reclining mechanism. If the reclining mechanism has been utilised; either for comfort whilst being occupied or to move the seat further into the vehicle side, this may be restricting the valve's working range. 
Once the seat is in its upright position, the seat cushion release valve should engage and allow you to move the seat cushion as intended.