Thank you for the reply.
Can you tell me what in the information makes them not eligible?
I had done some reading and thought it was stating that if the children were born before April of 2009 then they would be eligible if only one of their grandparents was Canadian born?
The first generation limit, defined under 3(3) of the current Citizenship Act, makes them ineligible. Unless the grandparent was a Crown servant at the time of the parent's birth, then the grandparent's status or circumstance is irrelevant in relation to the grandchild's eligibility; it is the parent's status at the time of the grandchild's birth that matters.
I had done some reading and thought it was stating that if the children were born before April of 2009 then they would be eligible if only one of their grandparents was Canadian born?
The OP's father would have ceased to be Canadian because dual citizenship was prohibited in 1967. He would have regained it in 2009 as a 'lost Canadian', and under the same legislation, the OP became eligible for citizenship by descent as the first generation born abroad through his/her father.