Buy a Universal Dry Verge End Cap from EasyMerchant
Black Universal Verge System (Dry Verge | Easy Trim) - National Plastics
Grey Easy-Trim Universal Dry Verge Kit/System - with 10 x Dry Verge Units and 1 x Domed Apex End Cap for Gable/Apex Roof fix to Any Tile -Mortar Free : Amazon.co.uk: DIY