annex

hi guys,
my british passport recently expired so now im trying to renew it but im having a difficult time with the c1 form.
im a british citizen having been naturalised around '05. now obviously i tick the yes box in that section. filling my own details is fine however my parents details are more of a problem for me. they too are british citizens (all of us being born in israel, and naturalised in the uk) so
(1) what do i put in as an immigration status seeing as how neither of them were living in the country the time of my birth.
(2) when it asks for the number of the citizenship document (this i presume is the naturalisation certificate) what do i put down:
-certificate no.
-the number written at the bottem right corner after the little black 'c' (not the same as cert. number)

i was also confused with the 'previous passports' section.
i have had a previous passport -israeli one. so when it asks for the number do i put down the israeli or the expired british one?
apart from that do i have to include my israeli passport in the documents i send?

thanks in advance for any help.