Scootopia made Lambretta series 1 & 2, Series 3 or DL / GP handlebar olive clamps, bolts, nuts and washers. 
 
(Did you know, Innocenti changed the hex head series 3 style bolt to a cross head screw on early production 125 Special & SX models)
 
Sticky's spanner's manual says - "Occasionally the U shaped bracket can distort the olive enough to make the gearchange stiff. This problem can also be caused by too much paint being applied inside the headset. Removing the paint from the olive recess with a Dremel can relieve the problem. Alternatively simply placing a washer underneath the bracket can relieve the pressure a little".
 
Please choose from the drop-down menu which ones you would like.
 
Picture 1 shows Series 1 & 2 type, picture 2 shows series 3 - Li, SX & TV type and picture 3 shows the GP & DL type of fixings. All are interchangable, it's just a case of using the original fixing type if you want to keep it as original as possible.