Thanks everyone. Consensus is that it's a chopped P '03. I find BAR Jim's suggestion that it was done by an armourer most interesting. The point clip, if that's not it's original shape, has been done very well and the armourer route is a convincing explanation for what appear to be it's original extended scales. The sawn off pommel could have occurred at any time later. I'll try and get the scales off soon and see what's beneath.
Thanks again all.