Re: You ended up with a Nissan Puke? Unlucky!
I'm not sure how Nissan managed it, but the Juke, despite being a smaller vehicle than the Qashqai, has worse real-world MPG figures.
As to the infernal beeping, odds are the machine thinks a door is open somewhere. Open and slam all of them, and that ought to do the trick.
One final thing: if you have a car with keyless entry, remember that you are the owner of a system that relies on "Security by Proximity". If a car criminal happens to turn up with a box of tricks which can amplify both the signal from the keys to the car, and from the car to the keys, then someone can fool the car into thinking the keys are right next to it, when in fact they are in your house several metres away.
This trick (and I rather think sophisticated criminals are building the boxes of tricks, then hiring them out to dimmer, bolder criminals) lets criminals get into a car and ransack it; it also lets them start it up and move it a few metres or so. Just far enough to get to the low-loader round the corner...