I am UIT POS and was just unable to buy a UDV Raptor at Dau L10. I there some restriction that you can't have Serco or Itani +600 and be able to buy them or is this a bug?

You need serco and itani neutral to buy it.

As far as I remember, you need "dislike" or better for both.
If you have +600 for one of the nations (Itani or Serco), you might have "hate" for the other and are therefore not allowed to buy the Raptor UDV.

Thanks! And that is why we stockpile ships in this game.

And that is why stockpiling ships is shitty.

In which sense? Being able to store multiple premium ships near key conflict zones or the absurdity of being able to own 1000+ of any given ship period? While I myself would love to see more scarcity in ship capacity at station docks, I doubt the idea would go over very well in suggestions.