Sorry to be boring by repeating myself.
Last year I was in Penang. I failed to get the cash from an ATM which did not 'pay out.'
I contacted Nationwide and they immediately refunded the amount. As I was 'abroad' at the time they did even require the formal complaints form but accepted a faxed letter setting out details.
I don't see why you should make any claim on the bank where the ATM was. You are a customer of Nationwide, the money was 'lost' from that account not from an account with the ATM bank. As a Nationwide customer they have a duty to protect you.
Good luck.
