Am I alone in getting fed up with people expecting a new Brexit vote?

Whichever way you voted just accept the majority vote, for good or bad.

My real concern is that we are being held to ransom, or even blackmailed, over our contribution to EU coffers.

In business a disagreement like this would go to arbitration. This would be out in the open and independent arbitrators would agree what was the correct figure, no argument anywhere.

The trade talks could then continue but that is more difficult to try to satisfy 27 different countries, each with its own agenda.