I'm another Hozelock shower convert. Great for muddy dogs and muddy boots.
The portashower is amazing. You just fill it with warm water from the tap, put the lid on and pump 10 or so times, and then it squirts for ages.
'last weekend we used in on the pony, and wrapped in a fleece blanket in the car it was still lovely and warm ages later'
You must have a big car to fit the pony in.