Oooops I booked the Tunnel rather than the ferry as usual for a change and did this months ago. Since booking I'be bought a roof box and I rang them up to ask about the height. I reckon I'm around 1.86.5 Over 1.85m I need to go in a higher train. However now there is no space on the times I have booked..... Can you risk it, what is their margin of error is it 1.85 and bang the roof at 1.85.1 ? I'm either going to have to ditch the roof box idea or risk playing happy daft when I turn up... but then could have a long wait / pay extra to be re allocated a train?