[Jim McDougall]

As far as I have known, the M1821 light and heavy cavalry trooper blades have a block ricasso and hollow ground blade, as seen in the picture. The blade OP in the paluoar seems to have the elliptical fuller which terminates at the ricasso area.
This elliptical fuller I believe is typical of M1853 blades and some of the later blades on British cavalry swords.
However, the M1853 cavalry sabre was the first to have the full tang (patented by Charles Reeves but Wilkinson also produced some under license from him). What was different about this tang was that rather than being inserted into grip, the grips were individual pieces sandwiched onto the tang.

This type of blade tang does not seem in accord with the hilt on this paluoar leaving a bit of a puzzle. The first of these type hilts by Wilkinson (1854) with Reeves also producing.
I have seen M1821 blades by Reeves which must have been about 1840s so the 1848 date seems possible for these as noted. The Reeves blades I saw were of the 'old' type block ricasso.

In a reference (Journal of Royal United Service Museum, Vol.42 #2, 1898, p.1148) it is noted that Enfield did not make swords around the time of Crimean War but that did begin producing some then. There were a good number from Germany (most I have seen were Kirschbaum) but Mole (also working with Wilkinson) produced some.
The problem with sword production in these times was mostly the stringent protocols on testing blades per regulations.

So my question is, why does this blade of apparent 1853 type have the old form tang (as it appears) and why the Enfield stamp? Could this be one of the prototypes of the M1853 produced at Enfield prior to the production using the new tang?
Then, why is this unusual blade on a paluoar?
The British were heavily involved in Afghanistan after the 1879 war in trying to maintain their strategic presence there, and were of course not only subsidizing the development of industry and military but certainly bringing in British materials and quite likely often covertly. When they began the creation of the factory in Kabul the idea was to produce British weapons with Afghan workers.
In discussions here over the years and with the research and paper done by Mahratt, some of the weapons created there are addressed. It does not seem implausible that an ENFIELD stamp might have been in use in Kabul in these endeavors, and that an imitation of the M1853 blade with old style tang might have resulted.

Perhaps this might explain this anomaly, and I hope my suggestion makes sense.