DVLA Provisional Application

Hi guys I’m filling out an application form for my first provisional driving license and I’ve got to the part where I have to provide a serial number for the ID I have provided which is my birth certificate and a payslip I’m just a bit confused as to where I can find the serial number on the documents, on my birth certificate I have 8 numbers in the top left corner and 5 letters followed by six number in the top right corner???? Help!