Why do you see a requirement to depart from the overhead? Why not plan to head for the VRP at J3 M1 and call Farnborough asap on leaving the Blackbushe circuit pattern, either from downwind R25 or from upwind if on R07. If Farnborough won't allow you through in good time you could orbit or just route around to the east side and rejoin track as appropriate. If Farnborough allow you to route through their overhead - hopefully you will be able to see it to your right side and "cuff it" direct.