dash speedo lights flicker polo 6n2

hi i have polo 6n2, speedo warning lights flicker. nothing wrong with the car. more like some loose connection.

i have checked the following:

battery terminals cleaned

fuses checked (all ok) and cleaned on top of battery cover

interior fuse box/fuses checked

checked the speedo with diagnostics and shows no codes

checked battery negitive lead and earth points and wd40 them

checked, and replaced alternator and cleaned all the connecting points including cable

checked speedo cables and pins all nice and tight

checked battery and alternator with multimeter and shows all good voltage (with engine running and engine off)

not sure where else to look for?

any ideas?

diagnosed the whole system with my machine and no fault codes

warning lights only flickering for micro seconds now and again, not staying on.

cheers