Indeed a fascinating OLD thread!
Its funny, mentioning how in the OLD days, waiting for months and weeks for mail to be received....I think of my own fledgling days beginning collecting and research. It was in the mid 60s, and I still have old letters from communications researching various topics; museums, authors, dealers, collectors, the old envelopes a virtual stamp collection.
In those days it was international reply coupons (in lieu of SASE).
It took often months to get replies....in at least several cases, replies came over a year later!
When the computer came, it was amazing!!! and I will never forget beginning writing on this forum about 1997-98.
With Egerton (I have the 1880 edition, but use the Dover reprint)...This was a compilation of over 20,000 items held in the 'India Museum' established by the East India Co. in 1801. The first curator was Sir Charles Wilkins who was an orientalist who lived in India 1770 to 1786. He was said to have been the first Englishman who could read Sanskrit.
After dissolution of the EIC in 1858, the collections were moved in 1861 to Fife House in Whitehall; in 1869 to the India Office; then in 1875 to the British Museum, Kew Gardens and to South Kensington Museum (now Victoria & Albert (India Section opened in 1880. )
Lord Egerton of Tatton(b. 1832) by 1858 was seated in the House of Commons until 1883. However he was indeed in India for a short time c. 1855.
While he may have collected some items there, it would seem the majority of the weapons in the collections in the India Museum were already there by the time Egerton wrote his handbook. It is unclear what prompted him to write this, but it seems he had a profound interest in these arms and history as his reference is surprisingly accurate for the most part considering the dynamics of these collections being inventoried and moved. It would also seem that much of the identifications were likely carried out by the first curator Sir Charles Wilkins, who must have collected numerous items in his time in India. Also he would have had resources in sanskrit, as well as numerous items coming in from those returning from India.
Just how much Egerton himself might have collected is unclear, but overall as noted, he seems to have documented the inventories pretty well all considered.
As far as Indian arms in the Sudan, the case of the 'haladie' is a good case in point for a weapon regarded as having come from Rajasthan, but becoming quite well known in Sudan. I have also seen examples of tulwars with kaskara blades, and a pata with what is clearly a very old Sudanese blade.
That weapons of these regions of the British colonial empire somehow came together in these anomalies is intriguing, but not surprising.
As Gav notes, it would not be hard to imagine an uninitiated observer to presume a tulwar in Sudanese context was a 'variant' of the more familiar arms there. These kinds of circumstances are what make investigative research on arms so fascinating!