The Subtitle: 'Remembering Her Ladyship' - (The title is from the episode scene selection on the DVD Box Set).
The sinking of the Titanic was an excellent piece of writing it into the Upstairs Downstairs storyline, but as a 1970s, 'British' 'period drama' series, for me, there just wasn't enough drama.
There wasn't 'enough' drama from all the servants that honoured or remembered Lady Marjorie.
There wasn't 'enough' drama to honour or remember the deaths of the '3rd class' citizens/passengers aboard the Titanic, many of whom woulda been servants trying to escape 'the service' of servitude to households like Lady Marjorie's. It is also likely that Lady Marjorie's servants woulda had family members aboard The Titanic - there just simply wasn't enough drama about such an important, historic 'British' event that changed 'shipping laws' world-wide.
They certainly made enough drama about the war when war broke out during the series. They even brought other family members from 'Southwold' into the series.
At the time, the idea for a 'spin-off' series was floating around, and many suggestions put forward, but in the end, it was 'Thomas & Sarah' that was made & broadcast.
My suggestion for a spin-off series is & woulda been 'Remembering Her Ladyship'.
Using the available cast members and using footage from the series as a recap on the whole series, I woulda put together & got each of the servants to 'Remember Lady Marjorie' & have a single whole episode to themselves, just remembering their 'one-to-one' encounters with Lady Marjorie. This would have enabled & incorporated the works of other actors or writers.
In this day & age of 'remakes', and there's such a following or a global fascination about the sinking of the Titanic, there's no reason why that storyline couldn't be carried forward now, but time spent means that it wouldn't be the same without the younger versions of any living member of the original cast.