Surely the two soaps, JK (as was), and the odd ad-hoc Salford-based thing (e.g. Brexit/PM debates, etc) weren't/aren't the entirety of ITV's non-London output?
Judge Rinder is Salford I believe
Also according to wiki, Tipping Point is made in Bristol
The Chase is Elstree, does that count as London?
Also you aren't including the vast amount of non-studio based stuff, all the dramas, factual etc that makes up prime time.