Offshoreonly.com - Formula bolster seat parts

Looking for actuators and or parts, cables, buttons with plates. Just picked up some seats. One has the cylinder in it but no cable or button. the other has nothing. When I depress the valve on the one the seat will not stay down when I let go, also you can push it down without pushing valve lever down. Any help would be greatly appreciated. I've talked to P L Porter today and they are supposed to get back to me with a price but from what I've read on here these are not available and if you could find one they are out of my price range at $600 each?? sounds crazy to me!!

Thanks, Pete