trooper is displaying the silhouette as set out in 1858 - as described
by Henry Graham in "The Annals ot the Yeomanry Cavalry of
Wiltshire" (D.Marples & Co., Liverpool, 1886) :
"In 1858, some further alterations were made in the uniform.
The red stripes on the overalls were altered to white, as were also
the red facings on the tunic. The size of the shako was much reduced,
and an upright "shaving brush " red plume substituted for
the white horse-hair one."
is interesting to see a carbine displayed here.
"Monkey Tail" carbines were introduced in 1870 (ibid.) :
"Lord Ailesbury had a foot parade on the following Monday, and
addressed the Regiment (...) He said that Westley Richard carbines would
shortly be issued, though for his part he did not see that they were
wanted, as they had already a number of men armed with rifles (...)".
trooper seems to be wearing Field Day Order Dress - as described in
the "Rules and Regulations of the Royal Wiltshire Yeomanry Cavalry.
Approved hy the Right Hon. Qathorne Hardy, Secretary of State for War,
April 12, 1877." (ibid.) :
To be used generally for Summer Drills, Divisional and Brigade field
days, Garrison orderlies, mounted police in Garrison and Camp, and when
plumed and uncased
Boots and Spurs
Sword and Belts
Pouch and Belt
cloak, when worn on the saddle, will be rolled 40 inches in length."
shako would eventually be replaced in 1880 (ibid.) :
"In August, this year, the sanction of the Commander-in-Chief
was obtained to the change of the shakoes to busbies"