Bargain ferry

Have just been organising the ferry trip for our journey to the UK, now the Boulogne to Dover ferry has stopped we are going Calais to Dover, I found that there is a discount of 40% on SeaFrance ferries available through a UK company called Astus UK Ltd, basically, you phone them, you tell them your preferred date and time of booking and they book for you and you receive booking confirmation by Email.
The ferry worked out about 20 pounds cheaper than any other fare I could get.