I wanted to know moving forward is there a way to nominate my wife for the speeding offence and have the failure to identify charge against me dropped or at least some way to avoid points.
Not that I can think of.
Unfortunately you have already committed the FtP offence and court proceedings have begun against you. The speeding charge is a dead duck because the police do not know who was driving.
Unfortunately, apart from a hefty fine and a mandatory six points, a conviction for the offence will leave you with an endorsement code (MS90) which insurers hate and you will see a considerable increase in your premiums.
Is there anything other than you
"...rather stupidly forgot to send the correct drivers details within the required timeframe" on which you can elaborate.