Falcon over English Channel (1 Viewer)

I took a ferry from Caen to Dover yesterday afternoon and spent a little time on deck seawatching. Around 3pm, so half an hour in, I was alerted by a very dark falcon taking off from one of the lower decks, low over the water, heading rapidly back towards the French shore.

Immediate first impression was Eleonora's Falcon, and I should add it was clearly a captive bird as it had jesses attached to the legs.

Any ideas on how I should best report this? If someone is missing a bird....

Paul