US Passport Office don't hold records of my father's passport - he did have one - what can I do?

[Mich111]

I am trying to meet the transmission requirements to gain derivative citizenship through my father who was a US Citizen. The US Embassy will not accept his SSN records, even though it details all the employers he was employed with in the periods I need information for. My father left the US and lived in the UK with my mother for approx. 10 months in 1965 (which was after my birth) yet the passport agency do not hold any records on my father. I have been advised that, as he left the country, the determining factor in proving the transmission requirements is providing his passport records. My father did not use any other names and I have provided his SSN to aid the search but the passport office cannot find any records relating to him. This will in effect mean that my application for a passport will be turned down. I have also provided some school records for my father as well as employment records for a 9 year period. These are not being taken into consideration as although he was employed in the US, it has been stated that this doesn't necessarily mean he was physically present, although some of his jobs, such as taxi driver, deli assistant, hospital worker etc. would not include work overseas. I am now trying to obtain his Elementary School Records and information from the UKBA as to when he entered and left the UK. I have also been advised that there will be no border patrol records available for this period. I am at a loss as what do do next as my father is now deceased. Is there any other way of determining my father's physical presence in the US - which was on a continual basis from the late 30's to early 60's. He did not attend college but I am trying to find out if I can obtain details of any medical practiotioners he attended during his childhood. Any help or guidance would be very much appreciated as this has been a very long and arduous process and I don't wan't to fall at the last hurdle. Thank you so much for any help you can give - best wishes,