Doesn't the BBC contract out to production companies so that they're not liable as a huge organization for one small show's dumb actions? Seems odd, but maybe that's not a thing in the UK.
See through some things, but not through others? How about hiding billions of pounds worth of corrupt money in London real estate? Not so much.
That’s more of a problem of a lack of cases brought by the government than a problem with the courts. The courts have generally seen through such things quite well when the government actually brings forward cases.