The product that Tony uses is 3M Ventureshield.
It is applied by spraying water containing a small amount of detergent ( "Fairy Liquid" )
onto the panel, and ( after peeling off the backing paper ), onto both sides of the Protective Film.
The Film is placed in position and can slide around because of the water, until the position is just right.
A rubber "squeegee" ( block ) is then used to push out the water from under the film,
which then sticks itself onto the panel.
The film is quite tough and can be pulled back off and re-positioned several times
to get it in just the right spot, and can be stretched slightly to fit curved surfaces.
Instructions are provided with the kits he sells for "DIY" installation.
There's a video clip showing how the film is applied on the
3M Venture Shield Web Site