I already brought it to a garage and I'm reluctant to waste my time (and money) going to another one without first pinpointing where the noise is coming from. The garage I went to showed no initiative and little interest in tracking the cause and Ford CRC team were equally disappointing.
It clearly is something wrong with the car and how you think otherwise amazes me. If I tried to sell the car privately a potential buyer would ask about the noise and try to haggle using it as leverage or would walk away (which is what I would do). I wasn't actually thinking that the vehicle was unsafe but I don't expect this from a new car. If you ordered a new car and at delivery you saw a scratch, that clearly didn't compromise the safety of the car, then you'd still not accept it. If you choose to pay the premium to buy a new car then you are entitled to certain expectations.
I'm not expecting anyone here to somehow cure the problem from their armchair. I'm asking in the hope that a) someone might have had creaks that appear under the same circumstances and had corrective repairs carried out, or, b) that someone who is more knowledgeable about cars than myself would have the intuition to be able to suggest areas to check.