hi mark
done that one!
ok, look at the bottom chain safety guide ( i think this is what you meant right?) and you can pivot it off the back allen screw and at the front re drill the bracket so that it hangs lower down.
i did mine about 8-10mm lower and it works a treat. chain wear through the guide is just about equal and i've had the same rubber for about 4-5 seasons now.
i run 14/51 so....
regards
Taffy