Hi Dave
Toby is correct the reason for the backing could have been if he was on detachment to another regiment or just as Toby says a decoration by a previous owner but officially the answer is no backing
Regards
Clive
PS The only one that I have with a red backing is a badges of the Worcester Royal Gammer School OTC and they did wear a backing so it is possible one of the officers of this unit was a officer from the regiment at sometime