Barristers in 5KBW are regulated by the Bar Standards Board.
You can search the Barristers’ Register on the Bar Standards Board’s website here: https://www.barstandardsboard.org.uk/regulatory-requirements/the-barristers’-register/
This shows whether a barrister has a current practising certificate, and whether a barrister has any disciplinary findings, which are published on the Bar Standards Board’s website in accordance with their policy. Alternatively, you can contact the Bar Standards Board on +44 (0)20 7611 1444 to ask about this (or email contactus@barstandardsboard.org.uk).