In my opinion this was a bit racy for kids, but then it was a foreign film. The couple were on the bed and the drape around the bed was pulled shut. The man says "And now this." The wife replies, "All all right Bert, it's your birthday". I could have sworn that in my mind's eye, I saw what the guy did.
I just watched it today. He says that and then reaches out and gets a bottle of wine. I think it meant his wife was allowing him a drink of alcohol. Anything else inferred would go over any kid's head.
I don't think there was ever a cut scene showing Mr Perks getting it on with his wife! It's definitely implied, I think--especially as they have so many children ;) but as a child watching it it completely went over my head--I just thought he was allowed to have a drink before bed as a treat!
Also with the final scene, where Bobby tells her siblings to stay away from the house for a little while--I never understood that when I was little, but now I can't help but think it's so mummy and daddy can have some 'private time' lol!
When I first saw it I thought what he wanted was a drink, but could be implied that it led to something more, but it was only implied. Nothing unsuitable for kids.