I’m not sure the 'vents' you’re looking at in the luggage compartment are actually air vents. The five-seat Jolion has air vents in the rear of the centre console for back seat passengers, but since there’s no third row of seats, there’s no need for vents in the cargo area. Even if they were fitted, they’d direct air from the air-conditioning unit, not the outside where they could funnel rainwater inside.

A tail-light seal is a common source for boot leaks, though, so maybe it’s worth checking this again as the new seal may have been damaged when it was being fitted. But the real culprit is likely to be the rubber seal around the tailgate opening. This seal occupies a huge surface area, and even something is simple as a tiny scrap of fluff or a stray leaf or twig stuck to the rubber can cause a leak into the car.

The best way to chase a leak like this is to put somebody inside the cargo area with a torch, while you hose off the car’s exterior. Be sure to hose down the whole car (not just the area in question) as water leaks have a clever habit of starting in one spot and ending up in another. Hopefully, your observer will be able to spot where the water is entering the boot, and from there, you can home in on the leak.