Sorry guys,
I thought I had posted this a couple days after my original post. I did call back and spoke with a "manager". She said that my CX flight from HKG to TPE would count and there was no restriction that BA could not have a competing route.
Again sorry I did not post this earlier.
rich
ps. I still wonder what that agent was thinking as she was adamant that flights on routes that BA also served would not count toward the 20,000 Air Mile Promotion.