TP0216 Mainspring for Starr Revolver

I own an original Starr DA number 15022. The weapon has hardly been used but when shooting it the original main spring suddenly snapped. This is because it was thicker than this replacement spring and when the hammer was fully cocked it was forced to make a second bend over the screw retaining the rear trigger spring. This replacement spring requires a 1mm washer to lift it away from the frame but it works perfectly and it now misses the screw head that caused the second bend.