For households with more than a handful of hand tools, a large lockable outdoor storage box UK setup makes sense because it gives you room for gloves, compost scoops, plant feed, kneelers and longer-handled bits in one place. It is particularly useful when a smaller deck box would end up cluttered or force you to stack tools awkwardly.
The real advantage is day-to-day access. Bigger boxes are easier to load neatly, so you are less likely to rummage through a jumble each time you need secateurs or a trowel. A lockable lid also adds peace of mind if the box sits in a front garden, a shared space or anywhere visible from the street.
It is worth remembering that extra capacity is only useful when the shape works for your kit. A wider interior often matters more than the raw litre figure, particularly for storing spray bottles, tool bags and bulky seasonal items without wasting space.