We have 2A and 2L on an MD-11 (in January). I had assumed this was similar seating to BA F where 2A and 2K are 'next' to other, separated by the aisle. I haven't found an AZ saet map yet.
So far as MXP-LHR is concerned, isn't the lack of a seat number something to do with not reserving seats on shorthaul until shortly before take-off? My experience with AZ is some time ago, and I do not know current practice.