Osborne makes no outrageous claims, he offers basically the status quo plus the renegotiated reforms.
Its outrageous to make any claim about what a countries GDP would be in 14 years time, you would more accurate rolling a dice. Again, even if you rely on this, the country is still 31% richer than it is now. The report also assumes immigration remains at high levels.
So lets look at this £4,300 per household nonsense, this is GDP divided by number of households, which today is £60,000 ish, yet average income today is c. £40,000, so its already at least 50% inflated. The number of predicted households is flawed (immigration figures wrong) and your £4,300 is quite likely to turn into nothing.
Also don't forget the £4,300 is not less then what you have now, the report which you rely on predicts
if we leave we'll be richer in 14 years time.
it's Gove's who claims that we will be a part of "a free trade zone stretching from Iceland to Turkey that all European nations have access to" - which seems like a really attractive idea - except that such a free trade zone does not exist and no one has any immediate plans for forming one.
There is a an area from Iceland to Turkey in which there are no tariffs, the phrase 'free trade zone' seems accurate description of that area.
In theory yes, in practice:
http://bigstory.ap.org/article/982f8146e10942b2b7f6a07e2077576d/trump-nafta-trade-deal-disaster-says-hed-break-it
Breaking a free trade deal is an option for all countries.