"In order to succeed in a defamation claim in the UK, a claimant now needs to establish: (i) the “publication” of a statement, (ii) that the statement was about the claimant, (iii) that the statement was defamatory to the claimant, and (iv) that the defamatory statement met the threshold of “serious harm”, that is, that publication of the statement has caused, or is likely to cause, serious harm to the reputation of the claimant." (https://www.jdsupra.com/legalnews/defamation-claims-in-uk-require-proof-26759/)
In other words the burden of proof is on Farage, he has to show serious harm was done to his reputation.
I don't think Mr Bryant needs to worry, no matter where he utters
his opinion.