Possible Clues:

• "Killing Eve" assassin played by Jodie Comer
• Lines written in country house introducing new fashion magazine
• Country house girl introducing European verse form
• A poem with six verses, all ending with the first or last line of the first verse
• Poem of nineteen lines
• Poem: 'The Holiday Home, the Royal Mistress and Earl'
• Welsh town endlessly entering contest to produce a poem
• Welsh town shortly to enter contest for verse