I occasionally shuttle from Bicester to Oxford, and the track takes you through the edge of the danger area. Oxford Approach will confirm if the Danger area is live or not - if not then you're normally good to go. Best time is normally after 3/4pm or whenever they have finished dropping. Worth giving Oxford a call on the landline before you go to find out if they're hot or not.
On weekends the Danger Area remains active and hot, as occasionally they drop on weekends. The gliding club do not operate midweek.