Leave the illiterates be.
It was no drama, nothing caught fire, exploded or fell off.
The opening for the washer fluid is sightly narrower than the diameter of a 2p and is located between the fuse box and the wing, meaning you need to take great care to not soak the fuse box when filling (I filled it from a bottle rather than from a hose etc).
Total time taken: Less than 1 minute. Not bad!