2758: Thousa
The initial letter of all 24 Across solutions (whether clued or unclued), when read in clue order, reveal six examples of a quartet. Their significance is explained by the unclued lights when arranged in the correct order, with an apostrophe included. Across 5 Intimate talk that covers tea-pot and Minet (4,4) 9 Long-term jobs for support workers out East (7) 10 Irish waters, look! So horrible!