It appears that when the track control arm and bushes are replaced (as per OP's work) then the bolts are tightened in the UNLADEN WEIGHT position as per the Skoda docs in the link below.  It's hard to screw this up as the spigot on the rear end of the arm is hexagonal and fits into a similarly shaped hole in the new console bush. The front bush has a metal sleeve through which the bolt passes so no rubber is being sheared or twisted.

 

Noise most likely from front ARB droplinks  OR  ARB bushes - get some silicone lubricant from Halfords and give the ARB bushes a good spray. Worth a try for a fiver or so.  I do this a few times a year anyway - all the suspension bushes, bolts, links etc. Keeps corrosion at bay and makes it easier to service when the need arises

 

https://workshop-manuals.com/skoda/octavia-mk2/axles_steering/front_suspension_drive_shafts/summary_of_components_assembly_carrier_anti-roll_bar_track_control_arm_aluminium_assembly_carrier/removing_and_installing_track_control_arm_with_bracket_aluminium_assembly_carrier/

Edited 19 December, 20196 yr by Golf-Fiend
Forgot to mention ARB Bushes

21 minutes ago, Golf-Fiend said:

It appears that when the track control arm and bushes are replaced (as per OP's work) then the bolts are tightened in the UNLADEN WEIGHT position as per the Skoda docs in the link below.

 

It looks like T10096 is a special tool to lock the arm at the correct ride height corresponding to the unladen weight of the car without actually putting the weight of the car on it (makes access awkward to do with the wheel on, and can be risky to jack up the hub carrier whilst on axle stands). If the dealer used it there should be no problem.