Needed some adjustment
Just for info to anyone ordering this - this didn't fit my kitchen tap, as though the opening is wide enough on one side to fit onto a standard mixer tap, the opening on the other side is narrower and i couldn't push it onto the tap far enough for the tap to align with the rubber washer. This caused a bit of panic about where to find another one, until I realised I was able to use a hacksaw blade and metal file to widen the gap on the other side, and then this fitted perfectly.