This is and was the Irish Problem in mini form. Astute is British lives in Cumbria, doesn’t like the EU or Juncker. The ROI wants a sea border with Britain - the island of Ireland as one economic entity with both sides of the border in the Customs Union and a soft border separating the political entities. The EU has proposed that. The Northern Ireland population voted remain and therefore implied continued membership of the Customs Union.
It should be first point „done and dealt“. But, no. People like Astute and the quoted postal worker from Chatham don’t want that. They, through their government, together with religious wing nuts from the Protestant community won’t allow it. No wonder that there has been so much strife in Ireland.
I would be fuming if I were Irish or Northern Irish, and may even join a separatist party to break away from the UK if I were there. I see that as the only real solution to the Irish problem. What right has Astute to want to scupper a potential solution to the border problem? If he wants talks to progress, he should be for something which ROI, the majority of Northern Ireland through their remain vote, and the EU agree on. It has nothing to do with the rest of Britain in reality.