Very helpful pictures, Dibble.
Teodoro Reding – "red plastrons" suggests to me the LD uniform of 1812 pattern worn by the former heavy dragoon regiments of KGL from 1813.
According to the Osprey volume, the 1st KGL LDs initially wore the uniform of the Hanoverian 9th Cavalry. Is that what you refer to?
If so, I do not know what that uniform looked like.
The other 2 regiments are said to go straight into Hussar uniform, but I wonder if all 3 wore British LD uniforms of the period before – i.e. braided dolmans and Tarleton helmets. Alternatively, were Hanoverian cavalry uniforms of the same pattern?
I am still left wondering when the transition took place to the Hussar uniform.
So far as 1st LD (Hussars) are concerned, the question would seem to be whether the Hussar uniforms were adopted before they sailed for the Peninsular, where they disembarked in May-June 1809.
If still in LD rig, I imagine that they would have stayed in it for some time, including Talavera.
Given that the British regiments that adopted the Hussar style, 7th, 10th, 15th and 18th, were authorised to do so from December 1807, might it be reasonable to suppose at least that the KGL did not lag behind in adopting this style?
I am not sure how reliable contemporary nomenclature is as a guide to changes in uniform style. I believe all the British regiments remained officially Light Dragoon, including those (Hussars). This is reflected in the numbering.
Of course KGL differs here having Hussars 1-3 and LD 1-2, but the latter came about later, so their separate number sequence reflects their distinct origin as heavy dragoons.