I was under the impression that the valve switches over at high rpms, but when im under the bonnet revving the car, the lever on the side doesnt move?

Does this mean its not working, or the outside bit isnt supposed to move or maybe only while driving it is? Could someone please clarify.....

at the 3800rpm switch over poit you should see the piston leg move.. same when the car is started.... if no movement in both cases then something is wrong....