just been booking our trip to Bg., driving over and flying back, here are some useful sites for booking a ferry. The prices do differ so its worth comparing
Our crossing Dover to Calais for 2 plus car only cost £30, Saver.
N.B. Ferry from Venice to Greece. I chose to collect ticket from Port office at a cost of E10 which was cheapest option. Some show a fuel surcharge.
Tried to book flight back with BA, Sof/Hrow at £80 each but they are asking for a Bg. billing address.