Nick the engines from...possible UK. Then "sell" them to a friend in Lithuania. He will register the engines locally(as has a "sales" contract). The friend "sell" the engine back to You.
Now the engine has a official register document, sales contract, perfect documentation!
Now put it for sale on ebay...... I don't claim that is the case here but again who knows.
Somewhat suspicious that the Lithuanian register dock is dated so close the sales date.
fun on a boat is inversely proportional to size...sort of anyway