Hello CapnDave
With reference to the creation of the 13th Battalion Mounted Infantry.
I believe it was probably instigated towards the the end of 1900. Many British regiments created Mounted Infantry companies from their ranks.
See table below. ( December 1900)
In my humble opinion I believe your Grandfather Thomas was an infantryman on foot when he took part in the Tugela Heights and Relief of Ladysmith operations. His QSA medal rolls record him as being a Corporal having attained his clasps for Tugela Heights, Relief of Ladysmith, Cape Colony, Orange Free State and Transvaal. He was recorded as being a Sergeant on his KSA roll.
During 1901 to 1902 the Mounted Infantry were kept very busy on patrols, especially with railway lines and blockhouses. With regard to his action at Blaawkopje, Blaaukopje, Blauukop or Blaukop I couldn't find a definitive answer in connection to his MID. There were many skirmishes during the guerrilla phase of the conflict. It is very possible Blauukop / Kopje may refer to a hill or a farm where the action took place.
I found a couple of snippets for you to research further. However nothing relating to the 29th March 1902 unfortunately.
Action at No.4 Bridge, 5 Feb 1902
On 3 Feb 1902 a column under General Plumer made a drive from the east through Blaaukop which brought about a determined attempt by 200 Boers to cross the line. They made 9 separate attempts in the space of four hours.
Other actions were fought to prevent the enemy crossing the line and the battalion were also called upon to take part in drives.
Also, I found a casualty who was severely wounded on the 20th of February 1902 Near Blaauwkop. 5069 Private A Dadson of (The Queens Own) Royal West Kent Regiment, serving with the 13th Battalion Mounted Infantry.
Sorry I couldn't be more difinitve with the answers to your questions pertaining to your Grandfather. However, your idea of nipping over the border to the Border Museum may well be fruitful in your quest. I wish you luck and please let the forum know if you are successful.
Best regards
Dave.....
P.S.
In the British Army during 1902, a "King's Sergeant" was a rank bestowed as an honorary reward for distinguished service, particularly during the Second Boer War (1899-1902). While the rank was not a standard, established rank, it was used in some regiments to recognise exceptional conduct which would have been the case, reference his distinguished gallantry and MID. The 1911 census has your man still serving in the Borderers aged 35( Married) and rank of Colour Sergeant 2nd Battalion.
A professional soldier who fought for his country and sacrificed his life in 1914. His WW1 medal rolls pertain to him still being with the Border regiment having been awarded his trio. He was in action at the start of the war and was promoted to 2nd Lieutenant serving with the 1st Battalion Leicestershire Regiment. Alas, he was recorded missing in action presumed killed and he never made it to the Leicesters.