The end of the beginning. On Dorset coast at Studland Bay, 120 officers and ratings of HMS Purbec, aided by 100 Polish sailors, have cleared 22, 000 unexploded missiles from the 24 mi.?battlefront where, in 1942, a full dress rehearsal for the invasion of Europe took place, involving ships, aircraft, anti-tank bombs, mines and all the weapons of offensive warfare. Since 1 February of this year, HMS Purbeck , at first with the assistance of the army, has been engaged in rendering the battle area harmless. The first date set for the final 'all clear' was December, 1946, but demobilisation and other unexpected difficulties have slowed down operations. Priority farming lands have been cleared and already a third of the entire area has been rendered safe, though posted warning still advise people of the danger, usually invisible, of venturing forbidden territory. Photo shows, men exploding a rocket found at the water's edge during operations at Studland Bay. 18 August 1946