When will the defence of non est factum be successful?

[16] Edelweiss Credit Union v. Beck, [1991] B.C.J. No. 3183, (S.C.B.C.) states that "...if the defendant was genuinely mistaken as to the character of the document and that mistake was contributed to or caused by some misrepresentation by the plaintiff, even though innocent, the defence of non est factum will prevail".

There was one other case I was referred to and I find there is a distinction between the facts of this case and the facts in Coast Wholesale Appliances v. Armitstead, [1993] B.C.J. No 162, Jan/93 (B.C.C.A.)[ Coast]. In Coast there was an express [mis]representation as to the limited purpose of the application. That is not the case in these facts.