I only found out by chance when I wondered why Money failed to download?
I rang Nationwide on
08457 30 20 10 (08457 99 88 99 for credit cards); I requested to log an official complaint. I did and they said they would investigate and write back to me.
I complained about poor communication of this change to its customer and request that they at least allow download of .OFX files (as Barclays allows and many others); else I will move accounts to another company.
I encourage all of us to complain formally to Nationwide. We may not get full integration with MS Money

,
but at least allow .OFX download.