I’m a buyer for a large wholesaler and distributor. The glaringly obvious reason I do direct trade with e.g. Germany over New Zealand is the huge discrepancy in time/cost of haulage.

I’m not going to suddenly start buying/selling coffee from one of the countries in this deal when, even with all the extra red tape and costs when trading with the EU post-Brexit, it would still work out cheaper and vastly quicker to buy from/sell to the EU.