Not all channels have a rolling 14day EPG, towards the end of each week the terrestrial channels (and BBC specifically) usually work down to a 7day guide before then being populated during Friday/Saturday. Whereas Sky Cinema (for one example) tends to be rolling 14days. Also Channel 5 can be prone to random slots having TBA even a few days beforehand. So firstly, is this affecting certain channels?
But secondly... is this a problem with your box not connecting to the VM network... you can check under Home > Help & Settings > Settings > Network Connection. You're looking for a successful connection roughly every 5-6hours or so, and the last one should be "Successful" or "ok" with an option to manually force one there and then.
These should help identify if yours is just a problem with certain channels not populating their guide, your box having problems connecting, or something else besides.