Mrs Pink is absolutely correct, the reception center has to fax all the documents over to defra and they take about 4 hours to fax an approval reply. Since we moved to the UK before our dogs did, I actually met with the UK Reception Staff before we returned to the US to get the dogs.
We reviewed all my documents and they gave me a direct line to fax them to before we departed the US. This made me feel better knowing the documents would be there before we landed, and the staff knew who I was if there were problems.
Wishing you the best!