Riding home from Cologne. Help me decide.

[JJ]

I have a conference to attend in Cologne in a couple of weeks time.  I've just booked a one-way ticket plus bike, and a ferry from the Hook of Holland to Harwich.  The conf finishes at 4.30, so even if I chat to customers afterwards, a 6 or 7pm departure is realistic, and the ferry is 10.30 next day.  DHL can bring the laptop and street clothes home.

Shall I just make it a ride of 260 or so km, or shall I deviate a bit and make it a DIY 300?
Any route recommendations?

I don't think adding the UK bit to make a 400 is feasible given a 9 hour crossing.

[MSeries]

I think I'd just ride direct to be sure of making the ferry with time to spare. Navigating in foreign lands at night may add more stress so I'd not want to be pushed for time too. Good plan though, go for it.