I've had a Sky HD box since April and although generally happy with it I'm becoming a little concerned about the amount of times it has frozen or locked up, requiring it to be disconnected from the mains to reset it. This has happened about 5 times since I've had it, and annoyingly has caused failed recordings on all occasions. I know that this averages out at only one lockup every 2-3 weeks, but do other users experience the same level of problem or do I have a particularly duff unit.