I'd agree. It's just standard metric fuel hose IIRC. 8mm ID x 13mm OD (usually just called 8x12), available at the dealer. I'd stick with the OEM BMW stuff, it lasts much longer than the generic hose from parts stores. If you need it in a hurry, go take the hose with you & just size it out there. Be sure you get high-pressure injection line, not low pressure fuel hose.
You might want to pick up a few clamps too, those anti-tamper BMW ones are silly and annoying to tighten properly.