Good Guess Amatikulu, but Royal Artillery would of been marked RGA, and was formed into brigades and batteries IIRC.
As for the one underneath, the middle letter looks like an R, but dont recall anything to them initials, nearest I can think of is HTS, which was the Hampshire regiment.
In most cases (but not all) the markings are (battalion)(regiment)(weapon number) sometimes company will be between regiment and weapon number.