From the Redbridge Roundabout (where the A406 crosses the A12) take the A406 north and then the left fork onto the M11. Leave the M11 to join the M25, travelling west. When you reach junction 25 take the A10 north to the first roundabout. Leave this going east along the A121, crossing two more roundabouts, till you reach the traffic lights just before Waltham Abbey (MacDonalds on your right). Go straight ahead following the B194. across two roundabouts and continuing along this road until you reach Stubbins Hall Lane on your left (marked with a red X on the map). Turn down this road and then bear left down the approach road to Lea Valley Country Park. Park at the end of this road next to the visitors centre and toilets (marked as a blue P on the map). From here you can enter the park - this particular place is near the hide from which Bittern may be seen. There are other entrances and parking places marked similarly on the map.