If this an iPhone your unlocking then a Nuc is not sent as Apple themselves unlock it centrally after Vodafone ask them to.
If it's another model.of phone then it can sometimes take an extra 10 days if Vodafone need to contact the manufacturer.
If this is an iPhone 》
An iPhone is not unlocked via inputting a Nuc {unlocking code} like other phone models are, but instead is unlocked remotely by Apple themselves and their Database.
So no actual Nuc is sent by Vodafone UK.
The Vodafone Network lets a person know by email it's unlocking has been requested to Apple after accepting your Nuc online unlock request. (Please Check Spam Inboxes too)
Please Note > The iPhone isn't actually usually unlocked to all networks at this stage when Vodafone email you.
What happens is Apple then process the Networks request and occasionally this can take Apple approximately from a few days upto a further 30+ days sometimes from Vodafone's email to complete an unlock request made by a Network.
To complete the process please periodically insert an active i.e. connects to mobile network data, alternative Networks Sim Card in the iPhone with hooking upto iTunes is only typically needed if its an iPhone 4 or older although it wouldn't harm to do so.
From the iPhone 5 onwards there's not normally the need to hook up to iTunes to complete the process.
When it's unlocked you should see a pop up message and the alternatives Networks name will show in the iPhone's status bar.
Current Phone >
Samsung Galaxy s²³ Ultra 512gb Phantom Black.
