PSB in July!!! How?

As much as I like purple sprouting broccoli (PSB), and eagerly await its arrival during the Hungry gap, I don't understand why I am harvesting it right now. Yes right now and its only July. Has anyone else harvested PSB recently, or about too?

The seed packet is from a reputable company. The seeds were packed early this year and expire 2011. According to the seed packet Broccoli (Sprouting) Early broccoli. Sow in March -May which I did and harvest the following year between February -May NOT July!
If someone can tell me why this has happened I would be pleased to know. Thanking in advance. Yours confused mangocheeks.

By the way, it was truly lovely, simply steamed and drizzled with a bit of olive oil.