To my big surprise this well-known Kung Fu Classic has no proper cast list yet. Not arrangened by importance and no role names (thanks to dubs?) Couldn't even find who plays the villainious Yogo master who should be a taiwanese actor too... Fortunatly I came across a trailer with cast credits (just a poor quality) but I managed to capture him. Again - surprise - I couldn't find him in the HKMDB...
Added him with 3 pictures
http://www.hkmdb.com/db/people/images.m ... ay_set=eng

Looks to me like the name is an alias for Poon Chuen Ling.
http://www.hkmdb.com/db/people/view.mht ... ay_set=eng

I went back to recheck the on-screen credits for the films of Poon Chuen Ling, where he is credited, all the films that I have show him as Poon Chuen Ling except for "File of Heroes". In "File of Heroes", the following two names appear in the cast list (they read down):

I had assumed that the name on the left (Poon Chun Ling) was an alias for Poon Chuen Ling, since he is seen in the film, and the first and last characters are the same. But the name on the right (Poon Chun Lam) is an exact match with the name from One Armed Boxer. So there may be some other answer. (There might be brothers, but in File of Heroes there was only one actor with that appearance, and he looks to me like Poon Chuen Ling.)