Yesterday when I noticed the leak into the boot from the tailgate brake lamp, I noticed the lamp could lifted away from the glass by 1mm or so. Today it’s firm.

I wonder if the seal had dried out in the recent unusually hot weather and the recent rain water on it has expanded the seal slightly as there is no leak today!

Anyway I have ordered the new seal as below:

https://www.ebay.co.uk/itm/143406839475?ss...2749.l2649

It’s a design fault. The seal isn’t compliant enough. I’ve just stuck some c0.8mm double sided number plate tape around the aperture, leaving the protective film on the top side. Lamp sits snugly and tight now. Any thicker would be too much.

Not tested yet but fairly confident.

Thanks for the eBay link. Bought one in case my diy fails.

The fact there are so many on eBay shows it’s a known issue.

It’s a design fault. The seal isn’t compliant enough. I’ve just stuck some c0.8mm double sided number plate tape around the aperture, leaving the protective film on the top side. Lamp sits snugly and tight now. Any thicker would be too much.

Not tested yet but fairly confident.

This is what I ended up doing although I removed the protective tape so the assembly is stuck-down but I renewed the bulb beforehand to hopefully reduce the chance of having to replace it.
It's been though a few downpours now and so far so good!