And can offer a bit of reassurance?!
I am applying for a primary school reception place for my youngest starting next September, and have just completed the CAF through the Lambeth website (we will be returning to Streatham in August 2016). I don't have a proof of address for either myself nor my son (we own the house in Streatham we are returning to, but currently it is tenanted and so we don't have the proof of addresses that are required to upload to the site).
My DH works for the FCO and so we have been given a letter from them stating that we will be returning to this address, to use as proof of address, but I am still worried that it won't be accepted (I have heard rumours in the past that these FCO letters don't "work" when applying for primary places).
So I was just wondering if anyone else had had to do the same as us recently and had also been given this kind of letter and whether your DC then got in to the school you applied for?