Hi Lew and Tim, 
                        thanks for the info. Lew your's definately has similar features, but yours also seems to have more age  
 
 
    I began to think that mine maybe circa WW2 (blade profile very similar to the Fairbairn Skykes commando dagger) but your seems very similar in dimensions. 

 so now I am not so sure....I still think early 20th C . Could yours be mid=late 19th C ?