This is what they sent :
Thanks for getting in touch & were absolutely happy to help you with this - If your router supports a VPN Client then you can use the below files to connect to the secure VPN network here at DigibitUK - Remember that Sky / Virgin / BT and other Standard ISP Routers dont allow a VPN connection to be loaded.
Below is a link to the Certificates .zip file which will contain everything you need to get yourself up and running with the built in Zgemma OpenVPN Client.