I found the drivers 'arm rest' was a little low and hard for my liking so I came up with this. I cut down an unused PC keyboard wrist rest I had which just happened to be Black with a red top - so sympathetic colours to the GTi - and so far it has stayed attached just by sticking a strip of the hard half of Velcro to the underside of the wrist rest and pushing it down onto the arm rest.
Gives me just the right height increase and a softer rest for my elbow.