Right i have checked ferries here are the details
leave dover 4.40am friday arrive 7.10am
leave calias 5.40pm Sunday arrive 6.10pm
ferry cost £85 for 4 people
Fuel roughly £200
So total per person £71.25 plus very long drive

for me!!!
If any one up for it let me know and i will try and convince the wife
Oh and we would nead to leave at latest 10.30pm tonight