no i don't think its to do with any bond scheme, as far as i can remember it will only apply to those who are applying for a temporary visa not a settlement visa - as why would you have a bond repayable when you leave if your on a settlement visa, you would never get it back

maybe they want your current statement?, if your last one is 2 months old ??
if they do, as long as its not an online one, you could scan it and email to your wife and she could print it out