The Dunlop sandwich is tied so tightly to one corner of Scotland that the cheese is the whole identity. Dunlop is an Ayrshire cheese, made in the Cheddar manner but pressed and matured to stay softer, moister, and noticeably milder than the sharp English block it resembles. That gentleness is the point of the sandwich rather than a shortcoming. Where a mature Cheddar sandwich is built around a loud, slightly crumbly cheese that needs an aggressive pickle to stand up to it, the Dunlop build is the quieter version of the same idea, a mellow, creamy cheese that asks the rest of the sandwich to step back rather than fight.
The craft is in the cut and the restraint of the counter. Dunlop is more pliable than a hard Cheddar, so it slices thick and clean without the dry, mouth-coating effect a sharper cheese can give, and that softness is what lets it sit in a generous layer rather than a thin one. Because the cheese is mild, the acid counter is scaled down to match: a thin smear of a gentle chutney or a few slices of a sweet pickle rather than the assertive Branston a strong Cheddar would shrug off, since too sharp a pickle simply erases a cheese this delicate. The bread is plain and soft so it carries rather than competes, and butter underneath bridges the mild cheese to the crumb and stops any pickle vinegar soaking through.
The variations stay on the Ayrshire shelf and mostly argue about which light counter suits a soft cheese. The cheese-and-onion build adds a raw bite without overpowering it; a version with oatcakes instead of soft bread leans on a savoury, crumbling base the way the local cheeseboard does; a smoked Dunlop adds one extra savoury layer while keeping the mildness intact. Those deserve their own articles rather than being crowded in here.