Marsworth Reservoir
There's a cluster of reservoirs near where I grew up. I remember spending many hours walking their windswept circumference with my dad. We visited again when our eldest, Reuben, was around a year old.
The weather was bleak but the swans made for beautiful photos (I maintain that swans are essentially cheatcodes for photographers).
I prefer my 16-50mm lens for photography but here the 55-210mm really came into its own. I love the color contrast between water and reed.