Puzzles for July 26

Across

• 1 Main office splits into four sectors after boss' arrival (12)
• 9 City on Missouri apparently had administrators put their heads together (5)
• 10 To this overture I have added five notes initially producing desired result (9)
• 11 Not entirely off if teenager's two years older than Juliet (7)
• 12 The French originally Italian-born novelist inspired zealous German philosopher (7)
• 13 When he's a bit bigger, he'll come out of his shell (6,4)
• 15 Took the mickey out of a school activity then died (4)
• 18 Rough fabric, one of those that came over from Denmark (4)
• 19 A matter of life and death for tame viper I disturbed (10)
• 22 Hopelessness of the French couple (7)
• 24 Doctor claimed to be involved in treatment (7)
• 25 Be aware of large limits to understanding (9)
• 26 Latticework conceals roof space (5)
• 27 Mad scientist is matter-of-fact and incredibly intense (12)

Down

• 1 Recklessly high temperatures overwhelm 500 coniferous trees (9)
• 2 A pair of Charlies seizing mixed media lecturer (8)
• 3 Camilla gets stuck into risque entertainment (5)
• 4 Team up with reportedly a young female horse, not quite nine (9)
• 5 Plan time to get 26 reorganised (6)
• 6 Articulated control in period in power (5)
• 7 Creamy dessert served up with a hot fibrous vegetable (6)
• 8 Grabbed sixteen for the French deputy head (6)
• 14 University town roughly where The Archers is set (9)
• 16 2240 pounds given to Andrew Mountbatten-Windsor once in university town (9)
• 17 Her award for refurbishing monitors, keyboards, printers and so on (8)
• 18 Expert in martial arts starts to jump up and down... Acceptable answer!(6)
• 20 Intertwine clean components with bed stuffing (6)
• 21 Marsh holds everyone killed in battle (6)
• 23 Scrub some of this courtyard (5)
• 24 Egghead gets involved in return of staunch encounters (5)