Anyone travelled to DLP using Hull/Zeebrugge ferry?

[gembeans]

We are thinking of doing a trip to DLP next summer as part of a road tripping hol in France. I'm trying to get an idea of how much the ferry might cost in the summer holidays. Has anyone travelled this route in the summer hols that would be happy to share how much it cost? Sept this year is coming out at £350 but don't know what the mark up is for school hols.

Thanks
Gem