L322 2006 automatic gearbox thumps down gear when cold

HI, iv'e had this problem for a while now. When i leave the car over night to cool down fully, i go out in it in the morning and for the first mile or so it thumps down from 3rd to 2nd {quite aggressive) and then not so bad from 2nd to 1st just as you are about to stop. Iv'e had the gearbox reconditioned along with valve body and ecu. All adaptations have been reset, fitted a reconditioned transfer box, changed all the front arms and ball joints. When the car has warmed up it drives 100% with no issues at all. Any help would be great fully appreciated.

If I remember correctly, I think there was a software update to correct hard downshifts.....but not sure if it was only applicable to the 2002-2005 or if it continued into the 2006 MY

look in here..

https://www.landyzone.co.uk/land-rover/the-zf-6hp26-service-procedure.341840/


If its the 6spd