That's a bit of an "oo-ee-oo" moment...but ARE they easy to nick? I mean, OK, old-type door locks, simple column steering lock, but who knows what else is in place on a given car? And then, assuming you've got your filthy hands on the motor and stashed it away out of sight - what ya gonna do with it?? Stands out like a sore thumb, even if you repaint it, and you can't offer it for sale as that would be an instant "go straight to jail, do not pass Go, do not collect £70K" scenario, even if you tried to alter its identity (pointless due to the low numbers). And even breaking it and offering the parts would get your front door battered down in no time. So there's no point in nicking it, unless you just wanted the practice or summat?
By the way, did consider joyriders but they'd be lucky to get 100 yards, or at least to the first bend, before they stuffed it, meaning you could probably drag them out of the car and beat them to a pulp before the police arrived.