I don't care about Harry Potter, except for his corduroy bomber, barn, Harrington, what the hell is that jacket?

It's not a Barbour jacket because that would be too posh for English cockney kids. Not a trucker. Not enough seams.

With classic bomber jackets, I see shearling and welt pockets. Or pilot jackets with no shearling and patch pockets mid-torso for navigation maps and cigarettes.

Need more detail?

Sorry, didn't mean to cut off his wand. It was especially made, presumably, by UK costumiers, Angels.

I would describe it as a zip-front ranch jacket.

Belstaff, the motorcyle jacket company, refers to this kind of cut as a blouson.

Quiksilver (below) has something close but the collar is different. It also comes in gunmetal grey.