It begins innocuously. You pull into the site, it looks about right, you get the kettle on. The slope, if you even notice it, seems entirely manageable. A couple of degrees at most. Barely worth mentioning. You're tired from the drive and the site is lovely and the kettle is on, and some battles simply aren't worth fighting at four in the afternoon.

By eleven that night, you are very much regretting this decision.

The slope you dismissed as barely worth mentioning turns out to be exactly worth mentioning at bedtime. You climb into bed get settled, and within approximately forty seconds the laws of physics have expressed their opinion. Your wife arrives at my side of the bed. Not dramatically — not a tumble or a lurch, just a slow, inevitable, gravitational opinion that the lower side of the mattress is where everyone should be. You both know what's happening. You don't discuss it. You just lie there, two adults wedged gently against the wall of our campervan, staring at the ceiling at slightly the wrong angle.

“The slope you dismissed at four in the afternoon turns out to be very much worth mentioning at eleven at night, when the laws of physics have expressed their opinion.”

This is the campervan levelling problem. Not dramatic. Not a crisis. Just a low-grade, all-night reminder that you didn't quite get it right.

The traditional solution involves chocks. Every campervan owner has them — those wedge-shaped plastic ramps you drive the wheels onto to nudge it up on the low side. In theory, a brilliant system. In practice, an intricate little ballet that plays out in campsite car parks across New Zealand every afternoon.

The spirit level itself deserves a moment of honest assessment. Ours lived on the kitchen bench — a small round bubble level that was entirely accurate and also entirely useless, because by the time you'd gone inside to check it you'd forgotten which corner was the problem, and by the time you'd gone back outside to address the problem you needed to go back inside to check. It is a fine instrument being applied to a fundamentally two-person problem in a way that requires at least three people and a radio.

The core issue is that you are trying to solve a four-variable problem — front, back, left, right — by adjusting one thing at a time, going away, checking the result of that one thing, coming back, adjusting a different thing, and so on, in a loop that has no natural end point other than exhaustion or darkness. Every adjustment affects the other variables. Fixing the side-to-side disturbs the front-to-back. Fixing the front-to-back undoes half the side-to-side. You are chasing a moving target on foot, in the late afternoon, while hungry.

The discomfort of sleeping on a slope is the most obvious consequence of getting this wrong, but it's far from the only one. An unlevel campervan is also quietly sabotaging several things you'd prefer it wasn't.

The Coromandel trip — the one I'm confessing to here — was a five-night stay. By night three I had developed a sophisticated system of small rolled towels deployed under the mattress on the low side to counteract the roll. My wife had developed a sophisticated opinion about why we should have just sorted the levelling properly when we arrived. Both of these things are true simultaneously. This is the nature of camper travel.

A proper levelling system resolves all of this — not just the sleep problem, but the whole ritual. A good digital level talks to your phone, shows you exactly how many degrees off you are in both directions, and lets you make precise adjustments from the driver's seat while you're still positioned. No spirit level on the kitchen bench, no repeated trudge between driver's door and side door, no optimistic rounding of “close enough” to “fine.” You pull in, check the reading, nudge forward or back, and you're done. Accurately done — not approximately, not hopefully, but actually done.

The difference in a campsite arrival is significant. Where the chock ritual used to absorb the better part of an hour and a mild domestic dispute, it now takes a few minutes and is genuinely undramatic. The campervan is level. We know it's level because the display says so with a precision that a bubble in a tube simply cannot match. The coffee stays where you put it. The fridge runs properly. The door behaves. And at eleven o'clock at night, we each stay on our respective sides of the bed, as nature intended.

“The van is level. We know it's level because the app says so. The coffee stays where you put it. And at eleven at night, we each stay on our own side of the bed, as nature intended.”

I won't pretend that getting a levelling system is a dramatic upgrade in the way that, say, a new awning feels dramatic. It's quiet. Nobody at the campsite is going to admire it. You just arrive, sort it in five minutes, and get on with enjoying the place you drove to. Which, when you think about it, is exactly what a good piece of kit should do.

The rolled towels are in a drawer somewhere. They can stay there.