I'm agreeing a lot with PPL above.
- Covid19 introduced a concept of not signing for a Proof of Delivery (international and domestic). This is a radical shift in the logistics industry, and I doubt the industry will revert back even when/if Covid19 subsides; I see it already here in France with La Poste; if you want a signed Proof of Delivery you pay more for this service which was once considered a long-standing default normality in logistics.
- The moment there is a hard border, visibility of what goes on is always reduced. Physically, the items do not have continuity of complete care and custody by the transporter, nor even the customs broker. The UK depended so much on Roll On Roll Off shipping infrastructure and the
government could not get their head around the fact you can't have free movement of goods without free movement of people. What was seamless pre-Brexit is interrupted with disjointed systems, many handovers, new actors, and a paper trail taking longer than a physical goods movement. Hell, even today the UK government''s stupid knee-jerk response of offering pitiful short-term visas for foreign truck drivers fell flat on it's arse; it's just a continuation of a grossly badly managed ill thought out major infrastructure change.
- We can also remind ourselves about the lack of air-freight too.
I wouldn't go as far as saying international buying and selling is a mugs game, but if you do it, be prepared to make sure the paper work is 100% correct and complete, and pick a suitable reputable company (often the incumbents like Royal Mail, La Poste etc.), and as a seller cover your ass with a higher service level, don't commit to any lead-times, and seek insurance which you hope a buyer is prepared to pay.
Everyone looses, no one gains, because mutual benefit got wiped off the agenda.