You can't take the CPL skill test without having passed all the ground exams so it makes sense to do the studying whilst hour building. If you have a full-time job, it can take 12-18 months to complete all the exams.
You also need to hold a PPL before you can enrol on a distance learning course.
For a UK JAA ground school, you will need to be able to get over to the UK a few times for the classroom courses and of course the exams.
However, whether it's a JAA licence or FAA licence or whichever regime that you need for work in Dubai, I can't say!!
Cheers
Whirls