Thanks for the tip, have turned it on in nHancer and SH3.
I use both to be honest, but tend to scan the horizon with arrow keys as my mouse resolution is configured for drawing on the map accurately. I've a wee button I can press on the mouse to change the resolution but its fiddly so I tend to leave it set for mapping.....means I have to drag it all over the place in the optic views, hence why I tend towards the keys