i noticed today the neck of the header tank moves but the bottle it self does not seem to be a little coolent leaking from the bottom of the neck with it joins to the bottle is this ment to move ?

It's not meant to leak mate, but yes the neck is desperate and fits onto the bottle. Try pushing and twisting it back down.

What Osty said. The overflow from the radiator pushes and pulls liquid through a hose attached to the bottom of the header tank. The neck into the engine bay is just for filling and checking the level. If it's leaking from that area it could be overflowing as there is to much liquid in there. Note there is also a small overflow hole just under the join to allow air to flow as the level rises and falls and overflowing coolant to exit.

 

If it's leaking I would check the level and the hose to the radiator for splits and the bottle itself