Unless they continued to make the same jacket, which I highly doubt, there is no way you are going to get the same jacket they sold four years ago. Even if you knew the exact stock code, they would have sold off the remainder in a sale ages ago, as that's how clothing stores work.
The only way you are ever going to find another is by hoping somebody sells it on eBay or scouring charity shops.... or if you see somebody wearing one and offer them money for it.
In short, I'd forget about it and look for another jacket.