I'm a Spark user but bought a Dji Mavic Pro yesterday in an official portuguese Dji distributor. I've flown with it for the first time today and the left side of the image is always blurred. I've done tests and this is definitely a lens/sensor misalignment. According to Dji Forums this is a valid reason for replacement. The problem is that I have a very important phto trip to Italy in one week and a half, and I need to have the Mavic there.

Question: will the physicial store where I bought the Mavic yesterday replace the Mavic with a new one right away?

Don't see why they wouldn't with a receipt and if their return policy allows you the exchange. I would give it a shot.

I would imagine under EU consumer rights and certainly in UK, straight back to retailer for a replacement/refund, they sold you a dud.

Yep, it is defective like my first Mavic.  It doesn't need repair; it needs REPLACING since you bought new.  That must be an old Mavic, because this problem hasn't resurfaced for awhile now.

One way to find out, it should still be covered under warranty.

If you had check that there is no dirt or moisture condensation on the camera, you can try to contact the retailer to see if they would do. If they won't help, you might need to send the drone in then.

Seems to be a fairly common QA problem with Mavics if you look on here and the other forums.  (Mine does it badly).
I'd exchange it while you still can.