Problem setting up WhatsApp on new iphone15

I have an iPhone 13 pro max  as my main and my wife had an Android Google Pixel 3, both have WhatsApp installed and running, both on the same Vodafone account.

I purchased a new iPhone 15 for my wife and in setting it up have screwed both WhatsApp setup's

Using the Apple transfer app I moved data from the Pixel 3 and setup the iPhone 15.

As the iPhone 15 needs an eSIM I managed the SIM transfer via my provider (Vodafone), this worked great and the iPhone 15 now works as a phone OK maintaining the original number.

I then proceeded to setup WhatsApp 

On the iPhone 15 I launched WhatsApp and started the install

Then it wants my phone number to verify my account. I initially tried using the number (now on the iPhone15 via the eSIM) no message came through (it wants a 6 digit passcode)

I then thought it wanted another phone (I thought just to authenticate the user) and put in the number for my iPhone 13

So after some faffing about I now have 2 phones with WhatsApp stuck at the new setup and I have lost the prior instal,

The iPhone 15 is not critical but the iPhone 13 is.

I have iCloud backup operating on the iphone13 and WhatsApp is set to backup.

Can anyone help unravel my screw up please?