Yes, you are correct about your assumption that the recipe calls for 6 2/3# LME. I feel comfortable saying so because canned LME comes in 3.3# cans, so 6.6# is easy to believe. Five pounds of DME also sounds fine, but I expect there is more malt in it that just that, or you are coming in pretty light for an ESB.
Now, lactic acid? I wouldn't expect that in a Fuller's ESB clone. Someone may come on here and dope slap me, and that's fine, but I would be very wary about that recipe.