If this was happening on a daily basis I would think there is a problem, either with the box, or with signal levels. I would leave it in case its an isolated incident, as V+ boxes do reboot from time to time. If it persists, and there are no area faults, then its time to call Customer Services.
Cable customer since 1993. Services: FH TV, Sky Sports & Movies (2xV+), Talk Unlim Telco, VIVID 100, Virgin PAYG Mobile
I'm really sorry to hear that you have been experiencing some issues with your set top box rebooting lately, this must be really annoying.
I've done some testing on things from my end and can see some errors being logged by the box, so would like to arrange for a technician to call out and investigate further for you. I've sent you a private message in order to get this arranged, please look to the top left of this page where you'll see a red envelope icon, click on this and you'll see my message.