Have you tried restarting both boxes, if turning both boxes off and on with the switch on the rear of the box doesn't work you can try doing a factory reset, you will not lose your recordings if you select the option to keep them on your main box, the mini box doesn't have this option as it has no recordings. As you say you can watch your recordings on the mini but not set them on the main box I would assume that the network connection between them is good, something you can check with the diagnostics but if all else fails you can try resetting the hub, which brings up another question are you just using the Virgin hub or also one of your own.