It is PG-13. This was announced a day or so after JJ said they had nothing left to do but color tweaking.
It was rated a week or two ago, but there were TV spots that came out after the rating still said not yet rated, presumably due to when they were produced.
I don’t know anything about UK ratings systems. But here, anyone can see a PG-13 film with a guardian present. It’s just that a bunch of 11 year olds can’t walk in by themselves, in theory (they probably can in reality). PG-13 did not exist during the OT years. It was made to find a middle ground when Temple of Doom came out, if I recall. The rating is fine by me, and certainly doesn’t indicate what I would consider “gore”.