About 3 years ago I got my full UK CAA CPL IR with Frozen ATPL. I managed to get a Malaysian Licence by just doing the Air Law exams. BUT, this process may have changed so please check with the Malaysian DCA. At that time they fully recognised the UK licences. With others like the Australian and FAA ones you had to do exams and flying.
British Guy, you may go through all the trouble to get a Malaysian licence but are you a Malaysian Citizen or do you have Malaysian Permanent Residency? Because at the moment Air Asia are not taking in any expats. I will post any news if I ever hear otherwise though.