The Continental System was not very strictly enforced under King Louis Napoleon, and my guess is that his mother Magdelena Morrin was not British. He might have registered before 1810 using her nationality. It would also explain his knack for foreign languages, writing fluently both in English and Dutch (and being a licensed teacher, probably in French as well).

Would be nice to trace back his personal history, I'll find out what local Beijerlandse historians know of him.