Moin, das ist einfach:
1st Life Guards - schwarz (gilt auch für die 2nd Life Guards)
Horse Guards - schwarz
1st (King's) Dragoon Guards - schwarz
1st (Royal) Dragoons - schwarz
2nd Dragoons (Royal Scots Greys) - grau
6th (Inniskilling) Dragoons - braun
Quelle:
From General Charles P. Ainslie's The Royal Regiment of Dragoons – The Historical Record of the First or The Royal Regiment of Dragoons; Chapman & Hall: London, 1887. pp. 106-107, quotes the 10th August 1799 Order from Horse Guards:
"GENERAL ORDERS.
The heavy cavalry, with the exception of the two regiments of Life Guards and Royal Regiment of Horse Guards, are to be mounted on nag-tailed horses.
The First, or King's Regiment of Dragoon Guards; the First, or Royal Regiment of Dragoons; the Third, or King's Own Regiment of Dragoons, are to be mounted on black nag-tailed horses.
The Second, or Queen's Regiment of Dragoon Guards, are to be mounted on nag-tailed horses of the colours of bay and brown.
The Second, or Royal North British Regiment of Dragoons, are to be mounted on nag-tailed grey horses.
All other regiments of heavy cavalry on the British establishment are to be mounted on nag-tailed horses of the colours of bay, brown, and chestnut.
The custom of mounting trumpeters on grey horses is to be discontinued, and they are in future to be mounted on horses of the colour or colours prescribed for the regiments to which they belong.
Harvey Calvert,
Adjutant-General.
Horse Guards
10th August, 1799."