uk citizenship and going back to Pakistan

[abc111]

hi
i am british citizen and would like to send my kids (who are also british citizens) to educate and settle in Pakistan and come back may be every summer to spend holidays. they are all younger than 6 years and i am concerned about their citizenship lapsing due to long term absence from uk specially if they don't come back here at all for years..!!

many thanks.

[CR001]

There is no 'absence limit' for British citizens!!

[abc111]

Many thanks.
What will be renewal procedure for passport. Will I be able to use Pakistani (not british citizens) friends as referees.

thanks.