In order to practise overseas you will need to be qualified in that jurisdiction.
Some countries (such as Australia where I practise now) only have a few extra requirements to become qualified as an Australian lawyer (provided you did the LLB) and many firms will take you on before you have undertaken those extra exams.
The fact that you might go down the CPE route would not necessarily be a disadvantage as the CPE would provide you with the necessary exemptions to get you to the same level as an LLB applicant. Obviously, that will depend on the relevant jurisdiction you're interested in. Overseas recruiters will be far more interested in the experience you have and, most importantly, the firm you worked for in the UK. All the Poms I know out here worked for top 20 City firms in the UK and came over between 2 and 5 years PQE.
Your best chance of working overseas is to work in a country which is based heavily on UK law - Oz and NZ are the best examples. The US will require a lot of further study (NY bar exam etc). China would, I expect, be extremely difficult to requalify into not least because of the language barrier.