What fert and rate for last dose on milling wheat will garantee a 13% protein?

[JCfarmer]

60 kg /ha of N as Nufol applied at boot split, seems to work as only had one claim from 9,700 T to Warburtons this year. All applied at night to avoid scorch and better uptake by the plant. Spoken to EA about the rate (on top of 220 kg N) they were happy as it has been applied using N sensor. the contract with Warburtons prevents us spraying it on the ear.

That's good going, Warburtons do however accept milling wheat at 12.5% protein without penalties. I have some contracted to them again this year but the majority to someone else for a higher premium but 13% protein.