 Complete the following phrase:  On the same day a new 21 Squadron was formed at RAF Bodney, still with the Blenheim, but re-equipped a few months later with the Lockheed Ventura. It was the first RAF squadron to use the Ventura, moving to RAF Methwold on 1 November. It flew its first operational mission using the Ventura, a low-level attack by three aircraft on railway lines near Hengelo in the Netherlands, on 3 November. On 6 December it took part in Operation Oyster, a large-scale attack by 2 Group on the Philips works at Eindhoven, with three of its aircraft being lost. The aircraft was never really suitable for the squadrons activities and they were replaced by October 1943 with the de Havilland Mosquito, having flown its last missions using the Ventura and the last Ventura operations by 2 Group on 9 September. The squadron turned to night raids on continental Europe; and from the end of 1943, like the rest of 2 Group, largely concentrated on Operation Crossbow, the campaign of attacks against V-1 flying bomb sites. 