Upvote:3
The local militaria shop owner is absolutely correct. It’s a 7-button home service undress frock as worn for smart working dress in barracks. The basic garment could have piping added in a variety of ways and some units chose to do so. The basic giveaway is the lower pocket flaps (the pocket was inset within the skirt of the jacket) and the absence of white piping down the front join. The frocks were made from a more coarse woollen material than the fine ‘cloth’ (as it was termed) of full dress and had a looser cut so that in colder weather it could be layered. However, after the 2nd Anglo/Boer War it became increasingly common for some units, especially regimental depots (such as is probably the case here) to encourage frocks to be worn for walking out dress in order to preserve in better condition the full dress tunics used for review order. The collar and cap insignia confirms that the regiment concerned is Prince Albert’s (Somerset) Light Infantry. I hope that helps. (“Frogsmile” Great War Forum)