As I said, I can't remember the specifics so it may not actually have been as high 40%. But it was a high figure and I remember somebody saying they expected the value of the euro to be higher than sterling. Most of the claims I'm referring to were made in statements from key Government people like Cameron, Osborne and Carney. Some were speeches and others written articles endorsing one report or another.
I didn't take a great deal of notice of Leave campaign claims or forecasts, and have never even heard of the one you referred to above. But "Project Fear", as it became known, wasn't a myth. Both sides were as bad as each other IMO and nobody presented a situation whereby they went through the pros and cons of both sides. They were either for or against, and it laid the foundations for what is now, in my mind, a largely irretrievable position.