@Uridium "Would really really love one, but alas I live in the UK, and the law isn't too keen on replica firearms here."
Ah, no, that's not a replica firearm.
According to the Violent Crime Reduction Act 2006 (VCRA) paragraphs 37/38 there is no offense if the replica in question does not replicate any specific modern firearm or generic design of modern firearm (modern firearms being those manufactured after 1870). The DS gun is obviously a fantasy design and not a specific or generic modern firearm. I would call that, for customs purposes, a gas barbeque lighter.