It is not acceptable to make contact with your examiners prior to your viva voce examination. It is against the University regulations and is taken seriously. 

If contact has been made between yourself, you supervisory team and the examination team It may lead to new examiners being appointed.

If you have any questions which you or your supervisory team would like to pose to your examiners then please log an enquiry from this FAQ. The RGS can then forward any questions directly to the examiner. The examiners response will be added to the enquiry.