Thanks for the sage advice! I agree and thanks!
I should add that if she is refused, it would be upon an excercise of the discretionary powers of the ECO. This is a case where we are not talking of missing documents, but of a guidance rule that gives them some leeway on how they apply certain other rules, which is what I am talking of. In other words, it becomes a matter of the personal judgement of the ECO as to whether the issue at hand is sufficient to warrant a refusal.
So you might argue at an appeal that the ECO used his discretionary powers to be unjust to the applicant, all things being considered. I don't want to go into the particulars of this but just as a generality. In any case, it seems like reapplying is a better choice than appealing.
Just as a supplementary, and I think I know the answer but want to be sure. I am thinking of changing my bank account and bank, because I can get a better interest rate in another bank. However, this is money I may need to show UKVI for the Financial Requirement purpose if she has to reapply.
They require the cash savings (category D) to be in an account in the sponsor's (in this case) control for 6 months before the date of application. However, it does not have to be in the SAME bank account (or bank) for this 6 months, does it?