There removed the back 2/3 row of seats of the Rear to accommodate the hospitality boxes in the 1st place
Do you mean to make them open planned than rather enclosed?
Just put normal seats in there. I’d say you could get 4 or 5 rows in there, I was in one of the boxes recently and there a lot of space wasted. I actually went and looked at the three stands after posting, there COULD be scope to put extra rows on all three stands, I think the structure behind would allow that.