It sounds like you do a thorough job there AA  

Mine usually gets cleaned twice a week.....even when its not been raining it still gets dusty.

My quick method....

Bucket of water, nothing added
Sponge...whichever one i find 1st
Quick sponge around the car.....skipping the wheels.
Two watering cans of water to rinse off (Hose pipe ban here!)
Chamois the windows......skip the rest (being silver it doesnt show water marks easily)

While its drip drying

Vacuum out the inside using a 14V rechargeable portable vac (quicker than dragging out the mains vacuum cleaner)
Wipe down the dash and anything else that looks dirty/dusty with detol fridge wipes (everything else ive tried leaves fibres behind and when dry looks just as dusty as before!)

15mins later job done  

Which is what its gonna get in a bit coz im off to Gatwick at 4 ish