As you can see, it's 170g and it serves 8 to 10 people. So, let's be generous and say each person gets around 20g.
But what's this on the front?
Yes, despite my poor photography you can probably make out that it says "Each 50g serving contains". So servings are 50g? That would mean a packet wouldn't contain enough for 4 people, let alone 8.
According to my wife, the difference is explained by the fact you add water to the stuffing before you serve it (presumably 30g or so per person). It still looks a bit of a swizz to me, though...