A bit late, but I had the same problem and it's easy to solve:
Remove the top half of the cyclone from the bottom part (5 x 10tx screws). This is a good opportunity to check the cyclone gasket and replace if necessary.
If the now floating red rod (with offset elbow) is still attached to the spring remove the two.
Drop the spring with two tabs into the bottom assembly. Grab the top of the spring with finger and thumb and twist it clockwise about 3/4 of a turn and hold it (a bit tricky at first), then whilst holding it, drop the 3mm protrusion of the jagged red rod into the spring so the horizontal portion of the rod effectively grabs the upper spring tab and stops the spring from moving back to its equilibrium state. Carefully guide the top part of the cyclone assembly with filter back onto the bottom half.
Hey Presto!
This basically forces the red rod over to the external side of the assembly where it's needed otherwise it would float freely and possibly catch the inner part.