I put the one shot nuts on today, but haven't tightened them to 290Nm. I don't doubt the caravan ones are meant to be torqued, but they're a different style. When the existing nuts came off they weren't torqued, and came off relatively easily, after I'd knocked out the pinch on them. I put them on tighter than finger tight (checked at 10 to 2 position on the wheel) that there was not lateral movement and not too tight that there would be bearing rumble when spun the wheel. There is no friction at all when tightening them, they literally screw on by hand, then ratchet for the last couple of turns. Happy with the setting, I then nipped them to engage with the cross-head on the stub axle, grease cap on, etc.
If they have to come off again, then obviously I'd renew the nuts. I will check them after the next trip out.
I've tightened driveshaft bolts on my own car (Audi Quattro avant), and they're on rediciously tight, and can only be achieved by using an extension bar to achieve the correct torque setting - so I know what 290Nm feels like.
Is that with or without VAT?