When flying for training out of Denham, the general direction is North West. This means (solo) students avoid going in Heathrow's airspace (or trying to find the small gap between Wycombe and Heathrow for a route to the south, and avoid going towards Luton. You can head NW and not infringe airspace for quite some time. My first solo navigation was around the Waddeson Manor gardens. It's a busy bit of sky.