Fire

Four unclued lights are of a kind and the remaining four can be arranged to indicate what unites them. Across 1               Woman with vintage Italian dress in racecourse (8) 6               Attack mischief maker with plastic gnu (6) 10            Electrical components in versatile robots (12) 11            Almost all wickerwork repelled essential oil (5) 13            Vehicle levy

Four pairs of unclued lights are all similarly linked.                 Across 5               Mark sample of class essays (6) 9               I’m beginning to like hot chap’s twinkling of an eye (10) 14            Beginning of oxidisation on iron container? (3) 17            One who chooses mixed ramen (5) 18            Of sound mind, regularly returns wearing gold ring (5) 20