I know what will stick it on, but you'll never get it back off again.. A mastic-gun tube of "The Works" - black sealant. But one tube will cost nearly £10 from Screwfix. Look for a few other rubber things that need repairing to make it worth while - or a few loose slates that need fixing. Sikaflex 252 is even better, if you can find a tube anywhere.

The overhead LED brake light on the rear tailgate keeps falling off on one side.

The LED bar is held into position by a brass plate which locates onto a rubber square fixed to the window glass. A series of dimples on the rubber plate lock into corresponding holes in the brass plate. Maybe because the rubber is getting old, the joint with the brass plate keeps failing.

I have tried strong glue, but it keeps failing. Probably because it is a rubber/metal joint exposed to strong sunlight and icy nights. Any ideas?

Small tube of Silicone RTV gasket cement shouldn`t break the bank and once you`ve used it ,the lid can be screwed back on for subsequent applications.You can get it in black ,should keep for 18 months if stored appropriately.