Has my friend been scammed?

Hi. In the UK here. Last night my friend met a young couple who were interested in buying his van for £2,200. They met outside of his house where there were CCTV cameras pointing directly at them. The girlfriend of the couple claimed to work at Toyota about an hour and a half away. My friend believed her as she was wearing a Toyota name tag and drove a Toyota car which she claimed was a company car. They also gave my friend their ‘address’. They agreed on the selling price, however only brought £300 cash with them and said they would need to send the rest via bank transfer. The man of the couple showed my friend his ‘banking app’ and the £1900 that supposedly left his account. However my friend did not receive the money in to his account. My friend trusted the couple and let them leave with the van before he received the money. It is now 9am the next morning and still no money has been received. My friend is refusing to believe he has been scammed. I told him to report it as soon as he told me last night but he wouldn’t. He rang the young man and the man told him that he would try and send the money again when he got home. I am trying to get through to my friend that he has been scammed. He seems to believe it’s the banks fault. Has this happened to anybody else?