Although the rank insignia for the British Army is fairly consistent, there are some variations in the rank badges worn by senior NCOs in some regiments, with an additional badge worn above the sergeant’s chevrons. The Royal Artillery had a small cannon badge, one of the hussar regiments had a small tower worn over their rank insignia etc. The Royal Engineers adopted a small flaming bomb or grenade that was worn above the chevrons for their sergeants and between the chevrons and crown for their staff sergeants. The bomb has nine flames indicating it is for the engineers rather than artillery use and this example probably dated back to the Second World War:

The moths have nibbled a bit of the backing felt but it is otherwise in good condition. A piece of cotton is glued to the back to protect the rear of the embroidery:

The quality of the embroidery is very fine on this example, however as the war went on these badges would be supplemented with printed examples to save costs and manufacturing capacity with universal use of embroidered insignia only resuming in the post war period. The use of the flaming bomb badge was also adopted by countries in the commonwealth and can be seen here being worn by a sergeant from the Royal Canadian Engineers in 1945: