Open banking providers recommendations?

QrizB

Looking at my banking apps, I'm offered the chance to "add another bank" by:

- Santander 

- Halifax (I'd expect Lloyds and BoS to be the same)

- NatWest

But not by:

- Nationwide 

- HSBC 

My only accounts with Halifax and NatWest are credit cards, so applying for a card might be an easy way to get access to their Open Banking if you don't have an option already?

dow

I bank with Santander, who have an exasperating 'feature' whereby they delete details of all payments  I've set up after 18 months - without asking me. Extremely galling, as they are are safe, secure and tested - unlike any I have to set up again. typically for Santander, my complaint fell on deaf ears.
I'm thus wondering if there is some sort of Open Banking provider that I could set payments up on instead, so that I'm not victim to Santander's hostile customer environment.