Parsnips are thought to be the worst keepers - but you don't have any of those.

I think the way you keep them is the most important thing. Air tight container, cool place. Unfortunately, you don't know how they have been kept by their previous owner.

Perhaps its me, but I could have sworn that my shop-bought seeds (kept warm and packets exposed to the light) haven't done as well as that from mail-order, over the years.

The best advice I have is to use them as soon as you can!