www.theguardian.com/politics/2020/oct/28/dfids-brexit-soy-sauce-price-cut-claim-prompts-backlash-bake-off
So I think I got this right.
We don't pay any tariffs on soy sauce at the moment due to a trade deal with Japan via the EU.
If we had left on WTO terms, we would pay 6% extra.
We have done a deal with Japan so if we leave the EU without a deal, we would have been paying WTO percentage tariffs.
Dept for Trade claim that the soy sauce used on Great British Bake Off will be cheaper thanks to the deal.
Really - they have stopped it getting more expensive.
(Oh - and as far as I am aware, a lot of our soy sauce doesn't come from Japan anyway)