Hi David....
I wear my mirrors a bit lower.
I've just had a look at some pics of mine and I'd say the bottom of the mirror is level with the rubber/plastic cover. If that's of any assistance when adjusting.
David,
FYI - I have also fitted the John Taylor (Phoenix Design) mirrors. Like Neil, I have the spindles set lower down in the holders with just an inch or so of the spindle showing above the black plastic seal. They adjust fine to give me a view just over the rear wheel arches, with a good field of view.
