Hi @soyaEnjoyer@hexbear.net, thank you very much for your reply.

It does seem like there might be an inner part, though very tightly fitted, I will have to see if I can pry it out. It’s good to know that a new screen would come with its own fixture as I didn’t want to risk any damage on the existing fitting if it turned out to be okay to re-use and simply find a new screen to fit in etc.

Thank you also for the tip re: the sealant and also for the wikihow article, really appreciate that :)