Think some parts for the Haenel XX will interchange with the Diana 20 so that might be an alternative source, but the barrels are not the same as far as I recall. If push comes to shove 1.6mm mild steel can form a reasonable trigger guard. I put a longitudinal bend it a piece then formed it to a profile on one a while back. No heat used just cold forming. Depends on function v originality & I didn't fancy a guardless one. Surprised me how much fun they were to shoot, great little things. Good luck with the search.