Cheers ivan, that's the kind of can-do attitude I was hoping for!
I have a plan that will make the drive more exciting, but in a good way. We won't book a ferry, but decide at the Barken exit for Bremen off the E22. If it's 0940 hours or earlier (check out the military time, that's how it's going to be), we'll head to Hook of Holland, if it's after, we'll head to Calais. We'll have an hour to check bookings before the route to Calais splits off at Osnabruck.
I reckon as long as we've got juice in the phones, numbers for the ferry companies and know how to check traffic/roadworks on the Hook of Holland route, this should work out pretty well.
Cheers all, I'm actually looking forward to the trip home now! 😀