Do I have to respond to the injunction if I am not in the jurisdiction?

This will depend whether you are out of the jurisdiction for a short time or whether you are resident out of the jurisdiction. If you are only way for a short time you must respond. If you are resident out of the jurisdiction this may depend on whether you were properly served with the injunction and/or if the civil proceedings accompanying the injunction were properly brought in England and Wales. You may be able to dispute the jurisdiction of the English Court, however, because the time periods for complying with a freezing injunction are so short you may need to comply with the disclosure obligations and then seek to challenge jurisdiction. 

Whilst the English Court cannot compel you to come to the jurisdiction to face a committal hearing, there will be a significant risk that you would be arrested if you ever came to England and Wales in the future. Failing to comply with the injunction will also harm your prospects of applying for its discharge, and possibly also your ability to successfully defend the claim. If you have assets within England and Wales these will be at risk if a judgment is obtained and enforcement proceedings brought whether or not you come into England and Wales.