were there any preparations made before the invasion?
Yes, a few Australians like Lieutenant Colonel Ronald McNicoll and Air Commodore Frank Bladin were involved.
Australian contribution to the Battle of Normandy
Few Australians were involved in planning the invasion. Some of those who had planning responsibilities included Lieutenant Colonel Ronald McNicoll, who served on the Operations Staff of the Supreme Headquarters Allied Expeditionary Force; Air Commodore Frank Bladin, Senior Air Staff Officer for No. 38 Group RAF; Lieutenant Commander Victor Smith, Flag Officer for British Assault Area's air planning officer; and Major Douglas Vincent, a signals officer attached to the headquarters of the British XXX Corps. 
what was australia's contribution to the battle of normandy? The army personnel and thousands of Australian airmen took part in the battle. was the battle fought in australia? UNANSWERABLE when was the battle fought? 1944 who fought in this battle? Australians and British was this battle part of a bigger war? UNANSWERABLE
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Australian contribution to the Battle of Normandy [SEP] Pre-invasion preparations
Bomber Command made 53 raids against these targets, of which 25 involved the four Australian heavy bomber squadrons. A total of 17 Australian bombers were lost during these operations, including six that German fighters shot down during an attack on the marshalling yards at Lille on the night of 10/11 May. In addition, Australians took part in 29 of the 46 raids conducted by 2TAF's light bombers against French railway infrastructure. Australian fighter pilots, including all of No. 453 Squadron on occasion, escorted some of these raids and conducted ground attack sorties targeting railway rolling stock. 2TAF's fighter-bombers also attacked bridges over the river Seine from April as part of an effort to seal off the Normandy region, and Australian pilots posted to British squadrons were involved in a small number of these operations.