I recieved this picture of 2 belts from a man whose great grandfather served in the 16th Lancers throughout WW1. The top picture is officially called a 'girdle' and was worn with best walking out blues by Lancers. I am unclear as to whether all the Lancers wore this same, yellow and red striped pattern, but I believe it might have been. The bottom picture is a classic stable belt of the period (seemingly in green) and lined in leather to stiffen it, probably for wearing when riding and/or bending over at stable parade.
With thanks to Bob Bennett