I don't see a huge amount or even a mere trickle of crude oil, iron ore, bauxite or other bulk commodities coming directly from the EU. I do though see transferred liberal quantities of overpriced foodstuffs courtesy of CAP guaranteed prices to French farmers. Presumably if hostilities haven't commenced in Europe then all will use the Channel Tunnel thus obviating the need for any gunboats - They could though do sterling work picking up Iranian channel swimmers who seem to have been persuaded that the pleasantries of life in GB exceeds that in their native land.
"the world is a much different place..". Human nature doesn't change. It still respects strength. There are three elements essential to the international projection of power: The will to do so, confidence, and well balanced and adequately sized and resourced military forces. Two out of three won't do it. If you believe you can, you will. If you believe you can't you won't.