Gaslight near York Minster...and a "mini-quiz"

I'm in York today & tomorrow for a meeting.

Fortunately I had a few minutes free to walk round this evening and take my blip. I wondered about a "straight" picture of York Minster; it is lovely but I blipped a photo of Lincoln Cathedral last week, which was rather similar. Then I noticed this old double gaslight just by the Minster. It still uses gas and mantles! (OK so really only one side was working so I had to copy the illuminated mantles from one side to the other in Photoshop.)

Here is the mini-quiz: can you spot which is the copied row of mantles and which is the original?!