Nigel Farage is now considering whether “life was worth living” in the UK.
Nigel Farage is now considering whether “life was worth living” in the UK.

What we know about Nigel Farage's claim he has been shut out of his bank accounts

That moment when you are walking down the street and you accidentally tread in a steaming pile of irony.
As it says in the article, he's been designated a PEP because he allegedly took money from the Russian government. He denies this but hasn't sued the person making the allegation. Even in his rant on GB news he lists Ukraine first as a potential state known for bribery. He excuses Russian actions at every turn, it's clear he's getting something from them.
He can't sue the person who made the allegation. It was an MP who made the allegation in the House of Commons. This means that the MP is protected by Parliamentary Privilege which allows an MP to say whatever they want while in parliament. Very important for allowing MPs to have proper debate without interference.
However, having said that. I definitely think he did accept money from Russia (the truth is also a defence against being sued!). He appeared on Russia Today (state propaganda) a lot.
He can't, because it was said under parliamentary privilege. An MP (in this case, Chris Bryant) cannot be sued for statements made in Parliament.
I'm not going to defend Farage (I think he's a slimeball) but the fact he hasn't sued is not evidence either way.
Setting aside the issue of whether-or-not he has received money, I don't think that it's a great idea to make the expected norm for someone to sue someone else if they're innocent of something that someone claims that they did. Kind of results in everyone running around with lawyers on hair-trigger.
Between normal people, or even minor celebrities, I would absolutely agree. But Farage is a notable entity in politics and journalism, one would hope that being accused of corruption, bribery, and treason would be ruinous for such a career. That is absolutely the sort of thing you would sue over, if you believed you had a good chance at winning.