Washer bottle leak

I've got a leaky washer bottle! If I fill it up to the line, the top ten inches or so in the 'neck' of the bottle drain out onto the pavement after about 10 minutes.

Not fatal since the main bottle holds water just fine. Just wondering if anyone else has been this issue?

I think it's the join between the funnel and the bottle itself.

Looked at Haynes, and it seems like a bit of a pain to fix, the wheel has to come off!