SOLUTION to Peter Cha3berlaix No. 812:

ACross - 1 RewArd, 4 Fizgig, 8 Ash, 10 Twin-tuB, 11 UnAlike, 12 Note, 13 Overweight, 15 KAngAroo Court, 18 PreternAturAl, 20 Worthwhile, 22 Agin, 24 NiAgArA, 25 Mixture, 26 Dip, 27 Astute, 28 InjeCt. Down - 1 RAt snAke, 2 Written up, 3 RotA, 5 InAdequAte, 6 Ooing, 7 Ohetto, 8 ABove one’s heAd, 9 HurriCAne lAmp, 14 HAve A heArt, 16 Tyre gAuge, 17 PlAngent, 19 RwAndA, 21 ReACt, 23 Oxen.