White Cocktail Store & Pour

Not on its own. UK law requires spirits to be sold in stamped 25ml or 35ml measures, which means a stamped thimble or a stamped optic. A measured pourer is a useful portion control tool but is not the legal instrument.

Sugar residue in the spout, almost always. Take it out, soak it in hot water and rinse it through. Pourers used for liqueurs need this far more often than ones used for gin or vodka.