I did exactly this for my Egli build( not fitted yet) I simply bought the "real Vincent chainguard", did away with the original fixings/brackets, cut away some "height", brazed some new brackets on. Really looks nice! Pictures of the bike whith out guard ;-) here: http://www.flickr.com/photos/dagsinclair/sets/72157629214714916/
Regards Dag
Regards Dag