I also left trough Spanish Africa (that way customs seems easier) to Europe trough Gibraltar (Algeciras) coming from Ceuta.
Bought the ticket while standing in line, the ferry person pointed to a booth to buy a ticket: got it and was allowed to enter.
Google Maps
I was happy with that because everybody seems to sell tickets but I don't know which time, which ferry: they might sell me an old newspaper.
Then again the customs check, nobody ever looked inside the crates on the roof, the customs guy pointed at me and said to his colleague that the landcruiser was a very strong car

And while I thought the checks would involve opening everything I just drove trough to the ferry parking.
One more check on the boat again with dogs (guy said people could hide inside the crates) but no trouble at all.
Next time I will leave the locks on, because I removed the locks they seemed to think someone could hide inside (?)
Oke this moment was kind of a relief, I should have booked a hotel in morocco to have a good safe sleep.