Firstly do not attempt now to move the boat , it could result in your prosecution.
If you have been in the EU , for over 18 months and your only claim is that you sailed outside the 12 mile limit then I would suggest you will have to " lawyer" up, because this could go to court. As I said previously while its technically correct , I suspect you would have to have third party confirmation or customs may simply not accept your current
No doubt they are using the Portuguese marina stay information as evidence , equally if you had a continuous contract
with one or more marinas
, that would indicate you had no desire to export the boat , even if you went outside the customs borders
Alternatively , you could agree a settlement without admission of liability and subsequently fight the issue in the courts. You have unfortunately fallen foul of one or two individuals who are very blinkered in their thinking.
Unfortunately The EU commercial
courts up and down the Union , are full of VAT cases, but customs don't always win
Also your Embassy and or the EU Commission contacts need to be used very carefully, if the customs are convinced they are right , such pressure can actually be counter productive, generating an extreme adversarial situation is not to your advantage. These people have a huge body of law behind them and considerable powers. You need to seek expert opinion
It has always been a criticism of the TIR directive , that it did not rigidly specify the exit requirements. The vagueness has been locally interpreted in different ways by different customs authorities.
This will either get resolved by Customs HQ telling their local office to let go , or you'll have to drag it into court.
Either way you need good legal and tax representatives , and it could get expensive
Best of luck