Before considering judicial review, first check the NOC code you used to confirm that it is most consistent with the main duties of your job. If it is, ask your employer to write a more detailed description of your duties and responsibilities. Email CHC London, attach the letter and ask if they would please re-consider your case based on additional information you have provided. Be polite and respectful(do not write in caps like your 1st post
Two fellas in the CEC section got refusals for different reasons and they emailed the VO with additional information and now their cases have been re-opened. Their status in ecas is back to "in-process". This is certainly more time efficient and cost effective.
If it doesn't work, then you can consider the judicial review process but it will cost you a lot of money and time, such that re-applying may be a better option. All the best.