Thanks everyone for your input.....I suspect one of these daggers will, again, be posted for comments in the future.
I suppose, to sum up, it is likely to be a quality Nimcha type dagger from the Algiers ( Ref; Oriental Arms) and probably ceremonial in nature, with a 'useable' blade.
It is a nice knife, hopefully new information will help decide how these knives should be catergorised and labelled but, until then I think the description above will have to suffice...