OK, you are still confusing HAVING citizenship with PROVING citizenship. Citizenship is something you have or do not have, and your passport has nothing to do with it. If your children showed up at the border without a passport, like anyone else they would not be able to get it. Same would go for you. Passports are essential for travel outside the country. HOWEVER, if they were in the UK and could produce their birth certificates and yours, thus showing that they have British citizenship by descent, they WOULD be allowed to live and work, and a passport is not necessary for this. Passports are TRAVEL documents. That is completely different to actually working and living in the UK. Passports are often the easiest way to prove citizenship, as you cannot get a passport without proving citizenship, but they are not the ONLY way.
An expired passport in my childrens case to me does not mean they still retain British citizenship - & I stick by that
Stick by it all you want, but you are still wrong! An expired passport is just an expired passport, it is not the magical giver of citizenship.
The BCI does not change the 1983 date stamp. All it changes is the 1961 date stamp. Children born before 1961 to British mothers were previously not allowed even to register with form UKM for British citizenship. Now they can, which makes them like all the children born between 1961 and 1983 to British mothers. In summary:
Child born overseas before 1961 to a British father married to the mother: automatic British citizen by descent
Child born overseas between 1961 and 1983 to a British father married to the mother: automatic British citizen by descent
Child born overseas after 1983 to a British father married to the mother: automatic British citizen by descent
Child born overseas before 1961 to a British mother married to the father: prior to BCI could not register as a British citizen at all (had to go through immigration process); after BCI can register
Child born overseas between 1961 and 1983 to a British mother married to the father: can register as a British citizen
Child born overseas after 1983 to a British mother married to the father: automatic British citizen by descent