DIY - replace UPVC double glazed unit

How to replace your double glazed glass in your UPVC window.
This video breaks the task down and shows you the simple DIY tools and techniques you need to do the job.
You will need :
A hammer
A palette knife or similar
A small block of wood
A tape measure
A long match stick, a pin and some adhesive tape.
Some cleaning materials - kitchen spray and plastic kitchen scourer
PRO TIP - These windows are externally glazed (meaning the glazing beads are removed from the outside, so they are less secure than internally glazed windows).
The PRO TIP is to put "silicone (sealant) between the frame and glass so you can't just take the unit out".