Why do West Lothian riders train at Straiton?
West Lothian journeys are motorway for most of the way: the M8 or M9 to the edge of Edinburgh, then the bypass round to Straiton. The drive is quick outside rush hour, and there is parking at the yard.
Because those routes are motorways, they are off-limits on a learner bike. If you want to ride to work on the M8 or M9, a CBT is not enough: you need a full licence, which Direct Access gets you in 4 or 5 days.