Just a couple of additions to the conversation. I've used the newspaper quotes for the gun sizes but I'm not sure the guns match the quotes.
"An Angel of Destruction. Lady Sophie Scott Firing a 4.7-in. Gun." They man hauled the guns down to the beach at Durban to test them before sending them to the front.
Navy & Army Illustrated Vol 10
A slightly better image of sighting the 4.7 inch gun
Image source: With the Flag to Pretoria, H. W. Wilson Vol 1 1900 and britishbattles.com Photo by Cribb. Half Tone Co. Ltd.
I happened across this high quality picture of the 10th, Mountain Battery. "No 10 Mountain Battery on The March In Natal, October, 1899"
Navy & Army Illustrated Vol 9 Photo by: T. H. Murray, Pieter Maritsburg.
I know everybody here knows this but just FYI: At the battle of Ladysmith, General White sent a detachment consisting of the 1st Battalion, the Royal Irish Fusiliers and half of the 1st Battalion, the Gloucestershire Regiment, with Number 10 Mountain Battery (equipped with RML 2.5-inch Mountain Guns) to capture a pass known as Nicholson's Nek which lay about 3 miles (4.8 km) to the northwest of Pepworth Hill. The force was commanded by Lieutenant-Colonel Carleton of the Royal Irish Fusiliers.