According to this article in The Telegraph the parents are Christians.
www.telegraph.co.uk/arts/main.jhtml?xml=/arts/2008/08/31/sv_thefamily.xml
It says "Simon and Jane are Christians and go to church every Sunday. Simon also runs Alpha courses, the 10-week introductions to Christianity, while Jane works full-time at a church-funded shelter for pregnant, homeless teenagers."
I think given that they are Christians they have a surprisingly refreshing attitude to how they are parenting their children.
The dad did come across as a bit of a dork last night, particularly when he sulked all night, was horrible to everyone, sent T om to bed early and then followed him up stairs and expected him to give him a kiss goodnight and got all mardy when he wouldn't. I think he sends out mixed messages, particularly to Tom - all disciplinarian one minute and acting like a child himself the next.
I also thought he was totally bang out of order to be so rude when Tom had his friend there.
Also, the mother must have been very young whe she had the first daughter (the one with the baby). If she's just turned 40 now she could only have been 17 or 18.