SOLUTION TO PRIZE CROSSWORD No 15,626:

ACROSS: 6 Open University. 9 Troops. 10 Primeval. 11 Isolated. 13 Instil. 15 Optics. 17 Throng. 19 Advert. 20 Eyeglass. 22 Unsettle. 24 Portal. 26 Leave of absence. DOWN: 1 Correspondence. 2 Demo. 3 Sunset. 4 Devilish. 5 Isle. 7 Impede. 8 Trading estates. 12 Lithe. 14 Stool. 16 Citation. 18 Genera. 21 Expose. 23 Envy. 25 Rink.