Draft representation, there is no boarding / alighting exemption here so it's down to a plea for discretion:
Dear London Borough of Tower Hamlets,
I would ask that the council consider cancelling the penalty charge notice for the following reasons. I had dropped my mum off to visit some relatives who live on the estate, who are unfortunately unaware of the parking provisions as they don't get many visitors who have a car. When it was time to pick her up, I stopped briefly in the bay with my mum's blue badge clearly displayed.
I had to go to the third floor to pick her up, as she has mobility issues and would not have been able to make it down to the car without assistance. I appreciate the observation time is quite long, but taking an elderly person with mobility issues down numerous flights of stairs is a time-consuming task as she can only take so many steps before having to stop for a break.
My car was only stopped temporarily for as long as was necessary for me to collect my mother, now that I am aware of the parking restriction I will of course make sure to obtain a permit on future occasions, but I would ask that on this one occasion you please consider exercising your discretion to cancel the penalty charge.
I attach both sides of her blue badge for your records.
Yours faithfully,