'He's serious about ranting against the EU. I can assure you he isn't serious about working out the minutiae of policy.'
Yes, but that is OK. Nor is Trump. Farage is a salesman, an orator, policy can be done by wonks. Trump will set directions but detail bores him, the wonks can do that.
'If he is serious then what is he serious about?'
He should be fighting for ordinary people, challenging political correctness, promoting business and jobs, challenging green energy taxes, promoting PR voting, lower taxation, more referenda and direct democracy, more NHS funding, etc some of which he does do.
' Instead he insulted his hosts in a vainglorious diatribe.'
That doesn't matter because most of the 17.5 million who voted to Leave would have liked to have said the same thing. Insulting the political class wins votes because the people are not keen on a lot of them, just as Trump insults the Republican Establishment.
'Where will Ukip's funding now come from? All of their financial backers were actually backing brexit rather than Ukip.'
That's right, UKIP will possibly collapse if Banks pulls out, which makes you wonder how committed Banks really was. The Establishment would like nothing better than for UKIP to collapse because UKIP is the only populist party we have and populism is now wreaking havoc on establishments across the EU and the world.
'If he were serious about Ukip having a future then why has he systematically rid his party of anyone with a talent for leadership for more than a decade? His methods can be ruthless and vile.'
That is a good question. There are whole websites devoted to that question by former UKIP people who know him well. Is Farage for real or does he mess up and allow farces to proliferate? I don't know.
'hence it is difficult to take him seriously.'
Yes, I fear you are probably right, which means that UKIP will end and the ex Tories will return to the Tories and the Establishment will breathe a sigh of relief as the old two party shuffle will continue once they have got rid of Corbyn from Labour.