Victorian ... ?? sabre

[Mark]

A colleague of mine surprised me at work with this beautiful, though aged,
Victorian-era sabre. Can anyone tell us which pattern it is, and maybe an approximate date? The guard has the little hinge thing on it, and an ornate "VR" crest (see photos that follow). Blade is etched with a partially-obscured maker's name:

FIRMAN & SONS
153
STRAND
????? (Conduit St.?)
LONDON

The proof mark is inside a sunburst. There are the faint remains of etched decoration on the blade, but no other visible inscriptions other than a repeat of the "VR" crest.

The obverse of the scabbard throat is embossed

E&W SEAGROVE
THE HARD
PORTSEA

Any insight would be appreciated.

Mark