Auto Discovery, no power from park

Hi , ive got a 2.5 tdi auto discovery N reg.
After being parked when you get back in and start up again, when i pull away it has no power and wont go anywhere, after disingaging the gear a few times it eventually picks up again, has anybody had a similar problem and what could it be ? it doesnt do this every time but when it does its a complete pain.

My first thoughts are for the transmission oil.

Check the level and condition of the gearbox oil.

drain it, change filter and oil

Its to do with the electronic throttle , make sure you start with your foot of the acc pedal. Then when you put your foot on the gas it gets the message that you want to accelerate.
I have come across this in a couple of edc 300 tdi autosHTSH