Correction: The name of the section in the sanctuary where he sat is called “South Nave” (not Stalls North – which is a nearby section) and it was right behind the church choir. It was right in front of the General Congregation and across from Prince Charles’ guests. And it most certainly is right in the sanctuary of the Collegiate Church of St Peter at Westminster.
Feif: http://www.theyeshivaworld.com/coffeeroom/topic/rating-gedolim