I've always found the Lille route to be more convenient and only once gone "out" via Brussels. But coming back on a Sunday I've come via Brussels. Not sure about a Monday morning run though.
The worst jams I've suffered going out were just after the border when there were road works and an accident. Added about an hour to the journey. Other than that I haven't had many issues.
Back in the day, when we went Dover-Ostend the journey was much easier.
|