In my area there are many disabled bays marked on the road directly out side the disabled persons door. Could that be done for you.
How far is the “green” from your house? Could you get a cable from your house to it?
An ideal situation would be to get a disabled bay next to the lamppost and get it adapted to a charger. Worth giving your local council a call to see if there’s anything they can do.
Personally I would be getting a charger at your mum’s it seems the obvious solution.