If you live, manage, or let a property near Porchester Terrace, you already know the realities of shared hallways, busy entrances, lift buttons, stair rails, and the odd mysterious mark on a landing wall.

If you live, work, or manage a property around Lancaster Gate, clean windows are one of those details that quietly change everything.

If you have ever looked down at a wine mark, a muddy footprint, or that mysterious dark patch by the sofa and thought, "Right, now what?" you are exactly who this guide is for.