Jeremy Hunt campaigned for Remain and then pushed for a second referendum when his side lost, so it's unclear why you think his anti-Brexit stance is worth remarking on. Are you thinking of someone else, perhaps?
Re: OBR. We're talking about food price inflation. The article you cite in turn cites the OBR, but (a) contrary to what you're suggesting the OBR doesn't have seem to have done any of its own analysis and (b) it only mentions Brexit twice, once about immigration and the other is a single paragraph which isn't about food price inflation. It says:
"Our trade forecast reflects our assumption that Brexit will result in the UK’s trade intensity being 15 per cent lower in the long run than if the UK had remained in the EU"
They don't define what "long run" means and they don't state where this assumption came from. That's the quality of the OBR's in-house analysis: there isn't any. That's not a huge surprise. The civil service has a poor track record of economic forecasting in all respects, but especially on anything to do with Brexit. The government forecast before the vote that voting to leave (not leaving, just voting to leave) would trigger an immediate recession in which between 500,000 and 800,000 jobs would be lost, due to "uncertainty". In fact the economy grew and unemployment fell.
They do then mention the "latest evidence suggests a significant adverse impact on UK trade", and cite two other papers. Both are only about claimed changes in UK/EU trade, not UK trade as a whole. The first ESRI paper relies on such complicated modelling it's not worth spending time on and their abstract asserts a dubious assumption right up front. The LSE paper states:
"Second, the implementation of the TCA triggered a small and only temporary decline in relative UK exports to the EU in 2021. These sharply fell in January, immediately following the introduction of the TCA, but quickly recovered within half a year"
It does say that the UK reduced imports from the EU significantly, but this would be expected given the currency value decline and that the EU external tariffs no longer discourage UK companies from importing from outside of Europe. The UK trade balance hasn't had a sudden improvement so it just means imports are now more balanced w.r.t. ROW.