Category C (Class 2) LGV / HGV training runs around Ipswich, Suffolk and uses the DVSA Test Centre in Ipswich. C is the category that allows you to drive a rigid vehicle over 3,500kg.
USB 2.0 is much faster than the DVD data rate. DVD 1x (slowest) write speed is 1.39MB/s. DVD 24x (fastest) write speed is 33.24MB/s. USB 2.0 write speed is up to 35MB/s. A 24x DVD max is about 32MB/s while USB2 max is about 60MB/s.
I do agree that USB flash drives are far better than CD/DVDs. The latest 3.0 version of USB drive has been added with new features than version 2.0. I experienced USB drive is better as it facilitate back up, provide password option and downloadable drives.