Unfortunately, I can't enlarge the second of the two thumbnails attached to your posting, but I believe it to be a picture of one of the two Mulliner Park Ward Cabriolets specially ordered by the Australian High Commission for the Royal tour of Australia in 1963. Despite the single headlamps, these two cars are actually Silver Cloud III LWBs, chassis nos being CAL37 and CAL39. One similar car was built by H J Mulliner on a LWB Silver Cloud II, chassis no LLCB16.