In 1760, when the new Landgrave Friedrich II reorganised his army, the three former militia regiments were reorganised into three "Garrison Battalions" of 4 companies each, and one standing battalion of "Garrison Grenadiers" of 4 companies. This is the latter and by the AWI this is Grenadier Regiment Rall of Trenton fame.
You can see from the attached schematic that the uniform is basically the same although some coat lace has been added and the mitre's back colours has changed. The green flag has been somewhat embellished as per the 'Prussification' of the army. Further worthy of note is the fact that while the mitre rear of other ranks was piped white, this piping is gold for NCOs.
This one-battalion regiment fought at the Battle of Warburg. In my Hessian army the regiments are normally of 2 battalions each of 500 men (5 bases per battalion) whereas I have made this stronger with 7 bases or 700 men. Figures are mostly Black Hussar with command from Foundry.