This picture is of a platoon of the 14th Battalion (2nd Barnsley Pals) taken in 1915 whilst at Hurdcott at Salisbury just prior to their departure for Egypt.
It can be seen that preparations are underway for their deployment to a hot country as these Officers and soldiers are wearing their newly issued Wolseley (or Pith) Helmet.
The Pugaree (strip of material wrapped around the helmet) can be clearly seen. It appears that the cap badges have been slipped into the top of the folds of the material. This would suggest that these are normal cap badges with sliders.