I am IPAF trained it dose take about a day to do the course , but you have to wait to get on one. I used to hire a 19mtr machine from my local hire shop. They did not ask if I was IPAF just gave me a demo of how to use the machine and the keys.
Without seeing a pcture is a bit difficult to give a price. It depends on a few things.
You said its 5/6 floors high, but how long.
How many sides need to be cleaned.
How many windows are there
Will you need to go onto the pavement/road to get to any of the building.
Will you need to put boards down when you are moving the machine , so you dont churn up grass/ soil.
What is access like to the area.
How many times will you have to move the picker.
If you want to have a word about it give me a ring.
You can get my contact details from my website