these units, raised to reinforce british during the campaign to occupy the seven island (Ionian islands), which were of french rule since 1807, and they were disbanded long before the GWI!
Their last "battle" was in 1810!
Interesting: During the battle of Myloi (St. Mavra i.e. Lefkada of today), Kolokotronis was a captain in the corps. He persuaded the local warlords (Albanians, Roumeliotes etc) who were offering their services to the french, to remain "neutral" making it easy for the British to take the citadelle and the island. Kolokotronis was promoted to major. Thus ending the first part of the occupation of the Ionian islands from the french. Only Corfu remains french till 1814 withdrawing after the relative treaty.
11 years later, now general of the greek forces, Theodoros Kolokotronis lead his troops during the GWI. Some images depicts him still wearing the helmet and the rank insignia (lion heads instead of epaulettes) of this unit. Helmet, cuirass (part of the officers kit) and lion heads rank insignia and weapons belonging to Kolokotronis are still surviving in Athens ethnological museum.
Outside the building of the museum there is a statue of Kolokotronis wearing the helmet, by the way his helmet was similar to the french carabiniers helmet and not as the cuirassiers one depicted in the Osprey image). It is supposed that higher ranks wore different shape of helmet than junior ranks ...
It is quite disputable whether Kolokotronis actually wore the helmet during the GWI, but it is nice to see the general, later fieldmarshal, to wear this uniform!
Another fact: commanding officer in the Greek Light Infantry was Church, who played some part later in the GWI.