[Plextalk] Plextalk PTX1

Hi I am thinking of purchasing my own Plextalk PTX1. I have a choice of buying either a device running version 3.04NZL or version 3.07aue. I wish to update the device to the current version 5.01 UK English. 5.01UK English is the only English version offered on the Plextalk website. Has anyone on the list purchased a Plextalk PTX1 running either of these versions (one offered in New Zealand and one offered in Australia) and has successfully updated to the standard 5.01UK English? Obviously it is a different English version and I am wondering if it is possible to update on top of an existing different English variation? Kind Regards Janine Smith