I've just paid the NHS surcharge (nicely rounded up for three years and stung for the currency exchange to USD) and received an email saying that I should return to my application and add the IHS number but was told during the payment process that this number would be automatically entered in the application. The application is completed, otherwise I wouldn't have been able to pay for it, so I don't see how I can add the IHS number (other than maybe writing it on the printed copy) so any advice about that would be much appreciated.
Also, am I right in thinking that I need to complete a sponsorship undertaking form?
Is it form SU07/12?

Thanks