How to safely access this window?

[Brutal biff]

Normal ladders and use the wheel of the car to foot the ladders

That's what I'd do

 

[Larry365]

If you just stick a car at the bottom, not a lot can go wrong. If the bottom can't slide out, then there is no danger.

Cherry picker wouldn't work. The underneath of the platform would be too close to the porch.

 

[PiKe]

The only two acceptable replies are;

1) Pay someone to do it
2) Get pvc-u window fitted

I want upvc but there's 6 windows that need doing so it'll be quite costly.