Many thanks gentlemen.
Yes the Sanskrit letters seemed to be IPI to me, or perhaps IPE. I had not looked into EPE. Unfortunately though, those letters do not match any officer of the Coldtream Guards in the period from 1855 (when the sword blade was made) up until about 1870 (so even assuming the blade could have been made in 1855 and then rehilted if the officer joined the Coldstream Guards at a later date). I am fairly certain though that this hilt is fairly early, as later Coldstream Guards hilts have a different look to them - straighter grip, less prominent pommel and thinner guards. This is an early one, so I suspect the hilt is the same date as the blade and the whole weapon dates to 1855. This is supported by the fact that Foot Guards officers had a penchant for these unusual straight thrusting blades in the 1850's and 60's, but not really later.
In regards to the Viscount coronet and cypher, I'm afraid that my photos are on imageshack and that has gone dead for me! However this aspect of the sword has been discussed at length on SFI (
http://www.swordforum.com/forums/sho...arly-Wilkinson ) where Robert Wilkinson-Latham has input. We are fairly sure that the letter is a D, which may relate to Viscount Dangan. Though there are some other options.
Lastly, yes the letters IPI/IPE/EPE may indeed relate to something other than name initials. Name initials are the most obvious, but in Britain at the time these would be incredibly unusual letters to match name initials - there are virtually no first names in use starting with I and none of the Coldstream officers have a name that could even remotely correspond to those letters. So I am left wondering if those three letters relate perhaps to a Latin family motto, or some other more obscure and harder to identify thing.
Many thanks for your help though - it's good to have confirmaton on those letters.
Matt