Reply received from Richardson tree owner but he has no info re Ethel after the marriage.
How available are divorce records for the 1960/70's?
I see (thanks Google) that if you don't know the date/case number of a divorce in the UK, a search over 10 years (5 years either side of your specified date) costs £45.
The difficulty with this of course is that if neither party wants to re-marry, then there is not much need to divorce, but simply separate and live with other partners.
So even if Charlie and Ethel's marriage didn't last, they may not have divorced. We have not found children, either.
Added: I have been trying to search other countries' death records with a birth date of 19/1/1928 for an Ethel, but no joy.