I think you're spot on there Mark, we are worrying too much and going stir crazy with this cold spell we're all going through......
My extensions are screwed on tight onto the tre then a lock nut the other side of the extension which really just keeps everything tight and steering rigid, Its done 4k and has been fine. If something did start to loosen you would notice straight away on the steering and toe in/out on the wheels.
Have a good weekend all......We are getting loads more snow up here at the mo......
AndyH