Redfalo has it spot on.
Technically, you have a 12kph minimum speed to get to intermediate controls, but the time limit is based on riding 1400km distance at that speed. You get no extra time for the extra 33km of LEL route. This would mean that the closing time between Great Easton and Loughton would be under two hours, potentially lulling slower riders into a trap.
So we assume a minimum speed of about 12.3kph between controls, meaning earlier closing times. But don't worry if you're a bit late or if you think you've a fighting chance of getting back in time, it will be fine.