I suspect it's one of these with the rear roof cut off,
https://www.bing.com/images/search?q=austin+sheerline&view=detailv2&&id=937171A5E4C2520FB457EE7FAFCDBFA6C87B1BF9&selectedIndex=42&ccid=8xydM0%2by&simid=608053085297314851&thid=OIP.Mf31c9d334fb223a5cfe1333d8098e5bbo0&ajaxhist=0
so looking...