Omitted middle name on application

Hi
My son has almost completed his application and not included his middle name. I am aware that he cannot just edit this but would like some advice on whether he should submit his application and then ask to add his middle name or whether this should be done before submitting his application. I am conscious that the deadline is soon.
Many thanks in advance.

Hi there, He can submit his application and then request for the middle name to be added. As long as he has provided Identity evidence showing his full name we can update it for him. Thanks, Angela

He has provided his NI number and passport number. How does he request the addition of his middle name once he has submitted his application. Thanks

Hi there, We can update it from his passport details. He can call us or contact us via the live chat option on his online account. Thanks, Angela

Thanks Angela for your help, it is very much appreciated.