I flew DTW/LHR last month in J and had one flight attendant was told by a FA that delta's policy only allowed me one drink.

I wasn't that happy to begin with because the flight got delayed 12 hours and only got a couple hours sleep in the hotel due to the way Delta handled the delay and I was on a paid J ticket and had an awful crew as far as service went and no fast track pass on arrival for passport control.

The one FA gave a double Bailey's on the rocks with dessert (I had asked for a glass of port or desert wine and was told none was catered on that flight and they didn't have the printed menus on the flight for some reason). Like I said lazy flight crew and 45 minutes later I wanted a second one and went to the galley and asked and the one flight attrednant had a real nasty attitude and said Delta's policy said they could only give me one bottle and I told her that two Bailey's still had less alcohol than one mini of most of the other liquors. She insisted she could only pour me one and another FA poured a mini for me and I asked for a second to take back to my seat and she did that.

Really ticked me off because they ended up running out of Bailey's during the flight and I found out someone I knew in Y had no trouble getting doubles.

And then were a flight LAS/DTW last year where I didn't get upgraded and used a HOOU for a vodka and the FA handed me two and laughed and said he was having a 2 for 1 special on his card so YMMV