Going in to SARS or not?

SARS has asked me to provide documentation to verify my baking details, and there is a paragraph at the bottom of the letter saying "Should you be required to provide relevant material to verify your banking particulars you are requested to submit it at your nearest branch within 21 business days, for all other verifications your relevant material may electronically be uploaded via e Filing. "

Is there no way to do this through SARS eFiling or do I need to brace the long branch queues?

Unfortunately bank detail verification usually needs to happen in person at the SARS branch. However you could try and call SARS on 0800 007 277 to ask them if it would be possible for them to provide a linking your profile so that you can upload these documents via SARS eFiling.