Chippie1

Hi all, New here. I stupidly smashed my outer rear light but managed to source a replacement but for the life of me cannot figure out how to remove the old light. There's virtually no access from the boot where the battery sits/no obvious clips or nuts. There's a plastic/rubber square(ish) patch between the inside edge of light and boot edge but again can't figure out how (and if I should) remove this. Any help would be appreciated. Thanks