What you on about? I'm saying that if Chicago wants to DM me his mum's bond numbers, I'll check if the win is legit or not, and I'm confirming that neither me nor anyone can do anything with the bond numbers alone.
I also have an inkling that NS&I has to have a bank account in their system for you already, rather than asking you for one to pay some money into. As, I suspect, there's 100s of thousands of people who have the maximum amount of premium bond and therefore bank details are needed to pay the sums out each month. Probably also for tax linkage purposes.
The main question with all this ... How did they contact her? If it was phone it's 99.99% a scam. NS&I don't call you for a sum of £25,000.