Richard,
I would put a silver flower where the plate was. It seems to me, that silver placed on the square of the hilt must have had a special meaning. If there is something, it is a silver flower with a diameter of 10-12 millimeters, and the fact that there was a silver square on yours could, like you write, mean that the hilt could have been taken off for some reason or other. They may have run out of silver flowers

, and used a little silver plate instead, but why a silver plate and not a little iron plate?
I know that someone on the forum has a tulwar with such a silver flower, but I don't remember where I have seen it – please show it and give the measures.
The blade seems to have a very long ricasso – how long is it?