All is now clear.
Double yellow lines mean 'no waiting'. However, loading and unloading IS permitted, provided it is seen to be continuous.
The time plate you saw means that not even loading or unloading is allowed between 8am and 6pm, but no waiting is allowed at any time.
You can try appealing on the grounds you were loading, but they will require proof. There is no special dispensation given to pregnant women, by the way.
But just to clarify, unless you were constantly loading from the time you parked up, you can't claim it is true.