The cheese ploughman's sandwich is a plated meal folded into bread, and the interesting thing about it is the logic of that transfer. The ploughman's lunch is a deconstructed arrangement: a wedge of Cheddar, a heap of pickle, cold ham, a halved apple, salad leaves, all laid out separately so the eater builds each forkful themselves. The sandwich version takes that same set of components and makes the structural decisions for you, committing the wedge, the pickle, the ham, the apple, and the leaves into a single fixed assembly. It is not a cheese and pickle with extras. It is a whole pub plate rebuilt as one object, and its character comes from how those five competing parts are arranged so they survive being closed up together.
The craft is sequencing and moisture defence, because this build has more wet elements than any plain cheese sandwich and each one fights the bread. The Cheddar is cut as a thick slab, not slices, both because the dish is named for the wedge and because that solid mass works as an internal wall holding the wetter parts off the crumb. The pickle goes on in a controlled stripe against the cheese rather than the bread. The apple, which browns and weeps the moment it is cut, is sliced thin and laid late so its crispness survives to the eating, and it sits inside the cheese rather than against the loaf. The ham adds salt and body without much liquid and is the easiest layer to place. The salad leaf is the one fragile, fresh note and goes nearest a buttered face so the butter shields it from the pickle's vinegar. Butter to the edges on both slices is the waterproofing the whole crowded thing depends on, and the bread is sturdy and plain because a soft loaf collapses under five fillings and an assertive crust would only add a sixth argument.
The variations mostly come from which elements survive the squeeze and which are dropped. A Stilton or Cheshire ploughman's swaps the wedge and changes the salt; a version that keeps the pickled onion and drops the apple pulls the whole thing sharper; the pared-down cheese and pickle is the same idea reduced to its two load-bearing parts. Each deserves its own article rather than being crowded in here.