At NCL you should be fine, so long as the bag you take it in does not have too many other wires around it. So I would wrap it in a disguising plastic bag (avoid nice wrapping paper) and put clothes around it. There's no security screen at LHR if connecting directly. Then in CCR pop into the almost unused baby room to do a quick wrap, perhaps using a gift bag given the impossibility of using scissors. CCR have metal knives however. If NCL security do want to look at it, which I think is highly unlikely, you can have a quiet word with the security agent to do so without spoiling the surprise. The alternative is to explain to hubby that you have a special gift for which he will need to wait, but require you to head through security first. Then text him when you are clear. Again I really doubt you would need to do that. NCL don't check for power on/off.