[oldtoolie]

Flat webbing strap around the handlebars.
Waterproof case on sale for £6.
Car satnav.
Job done.
The case has velcro belt loops on the back so it is attached and detached in about 20 sec. No interference with steering.

Here's the case:
streetline GPS bag

 

[mlukason]

Cool solution oldtoolie. I like the hood...I get a lot of glare around mid-day, this cover looks like it would probably help.