Willy a friend from Alloa gave a fly to copy, which he thinks is very successfull for catching trout, the fly was "Shimmy" and recipe he gave me is
Hook: #10
Thread: Black
Tail: Black Marabou
Body: Black Chenille
Ribbing: Flat or round silver tinsel
Head: Leadshot painted black with white spots both side imitating as eyes.
Hackle: Black cock hackle palmered down body.
Most of my client will not accept any changes to this fly, like using silver wire instead of tinsel or black & silver mini fritz and using bead instead of lead. I am sure this is actual recipe for Shimmy. Try it let me know the result.

Fish tastes better with Irn Bru