Kateb,
What is the relevance of "Morpeth" to your search for the record of the death of Margaret Dodds.
If she died in Tynemouth, then the death would have registered with the Tynemouth Registration District authorities, which covered the town of Tynemouth ( and also Seghill).
When you write that died "sometime after Sept 1914", do you have a time frame.. e.g. 1914-1930 ?
Michael Dixon