Help with U.K citizenship for former colony nationalists

Hello everyone,

I have a few questions.

I am a 24 year old Barbados native,Barbados is presently a commonwealth member. My mother was born in 1956, her mother in 1936 our country acquired our independence in 1966.

My grandfather (mother's dad) was unmarried to her mother, but left Barbados in 1957 for the U.K and renounced his Barbadian citizenship, he is now a citizen of the U.K.

My grandmother, mother and myself hold Barbadian passports.
My grandfather, grandmother, mother and myself were born in Barbados.

My questions are-

.Did my grandfather earn citizenship by naturalization, or by birth. If by birth was it because he was born in Barbados while it was a colony? I'm not sure if nationality by birth works for colonies or if he would of had to be born in the actual United Kingdom.

.Can my grandfather still apply for my mother (he has tried before in her early teens but it was rejected for some reason, they have record of his application)

.Can my grandfather apply for his grandkids, even if we are now over the age of 16?

.Can my grandfather apply for his grandkids without applying for his own child?

.Does my mother or grandmother have any right to acquiring British citizenship themselves without the aid of my grandfather living in the U.K, because they were born while Barbados was a colony even if they have Barbadian passports?

.If the only way my mother can obtain her citizenship is through my grandfather, how many years does my mother have to wait to apply for her childrens' citizenship?

.Can parents or grandparents apply for married children/grandchildren over the age of 21?

Duplicate post:
http://www.immigrationboards.com/viewtopic.php?t=16422