motorists' tears

Seeing as this could be accessed without the internet's recommended initial steps of 1: remove wheel and 2: remove mudguard, I fished the broken valve spigot thing out of the tube, then hoicked the pump assembly off the bottom of the screen wash jug, then sought my tub of glue-related bits. As I recall having successfully used the screen-skooshers recently it can't have been completely broken until quite recently, as the position of the leak causes the reservoir to completely empty, so was possibly tearing and twisting for a bit before breaking; whatever the cause, the two sides of the break didn't meet very well and there wasn't much mechanical strength in the glued repair, so a replacement doodah is now on the way.