I think a lot of UK banks are now support the openbanking API eg https://www.natwestgroup.com/who-we-are/contact-us/open-bank...
https://develop.hsbc.com/knowledge-article/get-started-open-...
https://develop.hsbc.com/knowledge-article/get-started-open-...
You need to be authorised by the national competent authority (NCA) and be in possession of an eIDAS or OBIE certificate.