Electoral Roll Close affecting mortgage

Hi there, apologies if this is in the wrong place, I'm a newbie and just wondering if anyone had any advice. Having finally gone through a lengthy divorce and financial settlement, my partner is trying now to get a mortgage. She has an excellent credit rating, but is not on the electoral roll, so her application has been declined (purely because of the electoral roll).

She's tried to get on the electoral roll, but it is apparently now closed until the end of November and it takes 2 months once open for it to update on Experian, meaning that she can't now get a mortgage until the end of January at the earliest!

Has anyone come across this before and is there any way around it?

Thanks in advance