Thanks BorgDog

It's done with a router/chamfer bit. Very easy to do really provided you have a nice straight perimeter/edge to work with. All this has been done with a hand held router rather than a router table.
Mesh done for both sides:

Upright with throttle:

It's starting to look like something now.
Edit: Ejection seat stickers turned up in the post:

These will be embedded into the build behind some acrylic - not sure where yet.