If you wish to complain to Ofcom about Bringing Up Baby on Channel 4, this is the link
Ofcom complaints form for a programme you have viewed
Don't expect miracles, but do submit your concerns. Remember the outrage over Big Brother. Complaints are more likely to increase media interest than to stop the programme, but this can be a good thing.
What to say?
Say what you feel! If you were upset or offended let them know. If you have facts, state them. Try to be objective, and avoid being overly sensational. Not always easy when you are emotional about a subject. Spread the word. Get everyone you know to complain. The more complaints, the more likely Ofcom are to act.