Of course trade would be impacted. Especially the disaster in NI. That was 100% obvious and widely written about bit people decided all that was worth it. I hope it was not purely because they are xenophobic twats, but that is much how it looks.
My MIL voted for Brexit. A few days after the result, when I expressed concerns with regard to wtf would happen in NI, I had to explain to her how not being in the EU jeopardised the Belfast agreement and therefore (potentially) peace in NI.
Her response was just "I didn't know that". I took all my willpower not to say "Well, you should have fucking educated yourself then". She's an intelligent, well-educated woman, votes Labour, not a racist, but still she didn't bother to find out the half of it before voting. She regrets it now.
She also said that the main reason for voting to leave was because she didn't think the Germans should be telling us what to do, considering that they lost the war and we won. (Shakes head in despair.)