please help... santander changed a sortcode on a standing order

No_Santander

I think Santander should take full responsibility of this issue.

1. Even if your Landlord's bank changed sort code. There will for sure be circulation of information to Santander, hence they should either update it correctly without telling you. Or I think they should have checked with you getting your consent.

2. Then base on what happened at step one, you did not authorize Santander to sent money to the account at Yorkshire Bank but it did happen. It is Santander taking money from your account and sent it out. So it should be Santander compesate you. This should be independent from if Santander can trace back money from Yorkshire bank.

3. Make sure you claim on your interest lost and your landlord's, it might be small, but it is still your money.

4. They are not nice to you, but they are simplying doing what the FCA asked them to do, communicate with customer clearly.