here at BA we often have crew sat at doors on their own!
A319... purser could be sat at 1L&R even if we ever had to return to base with 3 crew.
A321.. purser sits at doors 1 alone, crew member at doors 2 and 3 sit alone
B757.. CSD at doors 1 alone, purser at doors 3 alone, crew at doors 4 alone and if we ever went with 4 crew, number 2 at doors 2 alone
B767.. number 7 at doors 3R sits alone, where as there are 3 crew sat up at doors 2!!!
and in the UK, we have the 1:50 ratio