I've been trying to get a robust answer to this question but I've unfortunately not been able to because people have different opinions on this.
I haven't a clue.
I haven't an idea.
This doesn't sound correct to me because based on my understanding, it should be written with "got" and I'm not pretty sure whether this is grammatically correct or not. This probably works okay with "have" but as "haven't" stands for "have not", this seems wrong.
Thanks in advance.