Personally, I wouldn’t take notice of a few difference in rankings. Especially not with those two universities. If you were talking 5 to 20 then yes. But as a law professor said to me, the way they rank university courses is very broad. Lots of consideration of many things like how many face to face hours, quota of staff to students, student satisfaction & various other measures, some might not even really apply to you. As a result, you can be talking less than a % between adjacent rankings & not much more between 3-4 places.
It is more important to ensure you will be happy studying at either place. Also, investigate what modules outside of the mandatory ones are available. Do you want to do a third year dissertation, do they offer it, is it mandatory? And how are exams marked? Are there opportunities to do a year in industry or abroad etc? Again, if important to you.
One other point about rankings, they can change in quite a short space of time. Last year QMUL was top 10, now it’s dropped. York has risen but did drop etc. Not saying it’ll happen but you’re best off looking at a Uni which has been consistently good over time imo over one just because it’s in the top 10 now (unless you’re looking at 1-5 places as they tend not to move much). Hth