Slater continued in the instructing role both in the UK and in the Middle East and also flew with Nos. 20, 216 and 1 Squadrons.
RAF Bomber Command | The Sabre Squadron | RAF Sculthorpe | RAF Northolt | RAF Coastal Command | No. 33 Squadron RAF | No. 263 Squadron RAF | RAF Ringway | RAF Lakenheath | RAF Brize Norton | squadron | RAF Leuchars | Pacific Squadron | RAF Mount Pleasant | RAF Mildenhall | RAF Greenham Common | RAF Fighter Command | No. 45 Squadron RAF | No. 127 Squadron RAF | RAF Wyton | RAF Welford | RAF Valley | RAF Tangmere | RAF Search and Rescue Force | RAF Molesworth | RAF Lossiemouth | RAF Leeming | RAF Honington | RAF Coningsby | RAF Alconbury |
Three RAF squadrons were represented in Siam during the brief occupation: No. 20 Squadron RAF with Spitfire VIII aircraft, No. 211 Squadron RAF with de Havilland Mosquito VI aircraft, and a detachment of No. 685 Squadron RAF with Mosquito photo-reconnaissance aircraft.
He and his observer were credited with an aerial victory on 17 March 1917, when they shot down a Royal Aircraft Factory FE.2d from No. 20 Squadron RFC over Lomme.