DIY

Looks like the bodgers have been busy. Ideally you need a replacement rubber seal, but as a temporary measure, you could clean the old sealant out and use something like an automotive windscreen sealant e.g. Arbo.

Anything you do short of a replacement seal isn’t going to be pretty!

Have a look on the Woolies Trim website. They have a large selection of vehicle trim inserts (you will have to take a small piece of the existing trim out to ensure the replacement trim is the same). It’s not particularly expensive. The trim tends to shrink with age so don’t stretch it when you replace it. The bodged sealer will have to be removed too.