We bought with a north facing garden, previously it was always a big no no for me but the house itself was just what/where we wanted so that was one of the few compromises. The house itself is very light as the lounge is at the front with a massive floor to ceiling window, we’ll be putting patio doors in the back to help brighten the kitchen/diner but it’s actually not been that bad through this last winter.
The garden itself still gets a surprising amount of direct sunlight as there is plenty of space between the neighbouring houses.
If everything else is OK then I wouldn’t worry.
Edit: That sun calculator thing is brilliant.