Does the CBT really take 6 to 8 hours, even if you've ridden bikes on the road in the past?
When doing your CBT you'll almost certainly be in a group of 2 (or more) learners. The instructor will continue with the cone stuff for a fair bit of time until he thinks that all the group are ready for the actual road bit.
So basically yes, unless you're lucky enough to have another learner who can ride already as well as an instructor who is willing to run through the cone stuff fast and is confident in the two of you's ability...