Use Spitfires and Hurricanes in equal proportions. Add Typhoons and Tempests later in the War. Almost every type of aircraft made in Britain served in Western Europe. Often a type would be transferred to North Africa or the Far East when it was superseded by a newer design or Mark.
According to Ellis (1993) The proportions of types of aircraft in The UK in Dec 1942 were Fighter (93) Squadrons, Ground Attack (12), Medium and Heavy Bombers (17), Light bombers (8), Torpedo Bombers (8), Flying boat (9).
Commonwealth Air Forces.
A significant part of the United Kingdom’s air strength was made up from the Australians RAAF (55) Squadrons, Canadians RCAF (84) Squadrons, Indian (9) Squadrons, New Zealand RNZAF (28) Squadrons. These figures are for the whole war.
*Additionally in October 1942 in the Mediterranean Theatre, the South African SAAF independently fielded (17) Squadrons: (5) Fighter, (2) Tank Destroyer, (4) Bomber and (6) Recce.
The exigencies of war would mean that very few units would exactly match their Order of Battle. Combat would quickly reduce the strength of the fighting squadrons down.
* Some pictures from www.tankzone.co.uk
** Thanks to Scott Saylor for the pointers on these entries.