The end wall of MIL's bungalow is rendered, and a very small bit of the
render has cracked off - possibly it has been hit by a vehicle.

I'm sure that the right way to fix it is to mix up a small amount of
sand and cement, and add some PVA, trowel it on and wait for it to dry,
and then paint it white.

Is there something I can buy, ready-mixed in a tub that I can just slap
on and be done with? Preferably without it needing to be painted.