Tried out the Ultimate Finish snow foam I'd bought recently. Wasn't planning on washing the car, but a few direct bird poo strikes on the bonnet & drivers side while parked at Tesco had to be removed.
Foam didn't seem quite as thick as the Auto Rae Chem stuff I used previously, but it rinsed off easier, and more importantly removed all the crap without any trouble. Thankfully the paintwork was unmarked as I'd cleaned it quickly enough.
While the snow foam is intended as a pre cleaner, it left the car clean enough to not need anything else - and with rain forecast for tomorrow it wasn't worth spending too long cleaning anyway.