2725: Tandemonium?
Eight unclued lights comprise four pairs. Across 1 Doubling my carbon in low country (7) 12 American sanctimonious state at the top (6) 13 Geological fold running nicely round north east of south (8) 15 Treatise outline includes pretentious odds and ends (8) 17 General Secretary holds back brief register on new retailers (12) 18