I can find no trace of Dorothy's death in England & Wales and I've now checked right up until last year when she would have beed 106 years old! We have no reason to suggest that she would have died in Scotland or Northern Ireland, so it is most likely she died in North America, possibly Canada.
Following on from MWS's line on cousins, I've looked at descendants of the youngest of the three brothers, Henry, who was born in 1881. Henry married Mabel KINGSLAND in 1903 and they had two daughters, Elsie in 1907 and Doris M. in 1911. Elsie GEDGE married Charles H. MARTIN in 1930 and they had one son, John H MARTIN, who appears to have married twice and in each case all the offspring were daughters leading to marriages that resulted in yet more changes of surname.
Doris GEDGE married Charles G. JOHNSON in 1944 and they had one son, Steven G.F. JOHNSON born in 1951 at Brighton. Unfortunately the current Electoral Rolls show six Steven JOHNSONs living in Brighton, but not a Steven G.F. JOHNSON. Of course he could have left the district, or could have omitted to include his other initials, or could have merely ticked the privacy box on the Electoral Registration form making himself untraceable online at least.
So even if you find a relation, it's likely to be a fairly distant one, who may never have heard of the airman, if you manage to trace an address. For instance, in England & Wales between 2002 & 2020 there were over 880 Steven JOHNSONs listed, and there may be be quite a few others who aren't shown because they ticked the privacy box.
Tracing the death of Dorothy has to be done by province in Canada and the further west you go, the more stringent the privacy becomes. So by the time you get to Alberta it is easier to obtain the military secrets of North Korea!
Maurice
