In case anyone is looking for one, this one even with post from Aus would be cheaper than the ones on ebayUK
It looks the correct one.
https://www.ebay.co.uk/itm/Lucas-Miller-Brass-Headlamp-Headlight-Shell-7-1920s-1930s-Vintage/302823836770?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649