I have just been studying the situation regarding visitors to your (and my) home, especially over christmas.
Did you know that even if you have the maximum 6 people in your home, if a trafesman needs to enter your house, lets say to fix something, then he is exempt from the 'six' rule.
Come Christmas in my house, over and above the six, there will be two plumbers, one builder, two electricians - all tradesmen and all exempt.