Biplane N6985
This is a picture of a biplane with the markings of the RAF and number N6985. The date is not marked on the slide, but it is a plastic mount Kodachrome, so that means it is probably in the last 20 years.
This photo was added to the collection on December 13, 2016
http://www.airhistory.org.uk/dh/p822.html
...and the black aircraft left rear, G-APKH
http://www.fleetairarmarchive.net/aircraft/leopardmoth.htm