Sorry you thought my comment about the Twin Carousels was misleading, I must admit as a past user of a single Platform Ferranti INAS I would have just about given my right arm for 3+2t.
Given the kit was in "Nav" mode, or whatever it was called on Carousel for around 8 hours without DME update your 3 + 2t gives an error of 19 miles, does it not? More than enough to find the Islands, but obviously not enough to bomb by. That was solved by a pop up to radar check the position with around 50 miles to run, and of course the bombs themselveswere dropped on radar, so the INS was irrelevant to the bombrun,
AFAIK.
Sure, you need to have aligned the kit with TLC,
and and you need some luck in hoping 3 +2t "applies" on the night and that one of the platforms hasn't raced off to New York, Flamborough head or somewhere more exotic... but don't you always need a little good fortune war? FWIW White's book claims the position at pop up was around 1 mile out from the mid-position of the two platforms.