Yes indeed, the ad car is what was known as an Austin 1800 in the UK. Confusingly I think there was also a Morris 1800 version in the UK, although time may be playing tricks on my memory there!
The Morris Marina was a different car in the UK, see John215 link above. The UK Marina 1800 had a single carb version, & a twin carb version (using the MGB engine) which was known as the Marina TC in the UK.
Common cars in the 70s, don't see many around know! Strangely though I did see one in the town where I live just a few days ago (yes it was on the road, not at the scrapyard[:)])
Tony
<font size="1">1981 2L FHC Cavalry Blue - very original & not rusty!
1980 3.5L V8 DHC Regency Red - on the road again.</font id="size1">