This has come to light because Farage is a high-profile and very vocal personality.
But how many other, less prominent people have been (or are being) denied access to facilities such as bank accounts because of their views? And even if it may be rare now, how do we prevent it from become a growing trend in years to come?
We are increasingly seeing two worrying trends converge, 1) the tightening of control over individual's lives by institutions - banks and other multinational corporations, government departments, tech companies, etc, and 2) the increase of blacklisting or 'cancelling' people for holding views deemed undesirable by the major 'influencers' and leading classes in society.
When these two elements meet, there is huge potential for rendering people who are thought to hold 'non-PC' or 'controversial' views as non-persons if they don't fit the desired profile.
I doubt banks as a whole will 'learn their lesson', as this is become a trend embedded in society in general. This will probably just be treated as an embarrassing one-off mistake by Rose (and if they can't pin it all on her alone, other members of the board). Unless of course, more such cases come to light and it opens a whole can of worms showing a pattern of this kind of behaviour...