We're new Virgin customers as of last week, and I'm having an issue I don't understand. Whenever the box has been switched off/on standby (most often overnight) it initially displays a scrambled screen of coloured lines when it comes on. This sometimes lasts for an unpredictable number of minutes (minutes my toddler does not appreciate!) - is this normal? Is the box warming up? It doesn't seem to be a poor connection as it sorts itself out and then doesn't happen again until the next time the box is switched off?