I think Monzo’s identity provider is US-based, so not sure this will cause an issue. As long as they continue to follow the GDPR!
https://www.jumio.com/about/press-releases/jumio-partners-monzo/
Based in Palo Alto, California, and funded by Centana Growth Partners and Millennium Technology Value Partners, Jumio operates globally…
https://www.jumio.com/about/