730d gearbox VERY jerky when cold only

[ShemGlasgow]

Morning all,

My first post here so be gentle ;-)

Had my 2012 730d for good few months now. Using it as a motorway cruiser to get me to work around UK. Done about 11k miles since I've purchased it with 125k miles on the clock. Only 1 previous owner from new so car has been looked after.
Couple of months ago I started experiencing a bit of an issue with my gearbox. When starting up in the morning the car is very jerky. I've had loads of cars in my life with different issues but unsure if this is more specific to ZF boxes? Until temp gauge sits in the middle the car is a bit unpredictable. When pulling from the junction the car hesitates to change gears. Revs building up but gearbox is slow and when it eventually changes the car is all over the place and Traction Control alarm comes up. Also often on cold engine when slowing down quite rapidly ex. unexpected light change to red, gearbox cant keep up shifting down and the car stalls and needs starting up. Need to drive like a pensioner which can be a bit scary in the morning with heavy traffic when you need to join the rest of the drivers during school run.
No errors on my diagnostic tool.

Needless to say, when car is all warmed up, everything seems fine with shifting.

Just after a bit of an advice really.
Have recently spend few quid (£2k) getting the rocker cover oil leak sorted with few other things and a set of rubbers so need to know if I should prepare for a huge bill? Could this only be that gearbox needs servicing? Can't see any receipts for that in the folder but servicing been done by BMW so assuming that's not on their list as it's one of those 'sealed for life' bolloc..s.

Thoughts?