With the ATPL written I think you may be out of luck. I joined a long time ago and am no longer at CX but when I joined it was always a conversion and some exams were required depending on where your ATPL was from. Mine was FAA and I think I had to do around 6 of the HKCAD ATPL exams, there was some ground-school which mainly consisted of going over the questions and answers to get through the exams, this was done in Australia over the course of about a month including a bit of flying to tick boxes. The problem you have is you have not ever done the ATPL exams so they would most likely want you to do the full ground-school course which is the best part of a year as you have very little experience and haven't done the theory. They are not going to put you through that course as they don't have to as will have enough applicants who do meet the requirements.
Best bet is to email recruiting to get a definite answer but I am almost certain it will not be the news you want.