Hello @jerry.howitt​,
My name is Henry and I am happy to assist with your inquiry, and appreciate you contacting LastPass Support!
The LastPass authenticator secret key does not depend on the email address you have on your account and should not be affected by this change. However, in the authenticator app you may notice that the codes display the old email address. If you wish to update this, you will need to scan a new qr code.
Please let me know if this worked or if further assistance is required.
Thank you,
Henry | Customer Care
Henry. Thank you for your reply.
It was very nerve wracking as the consequences of it failing were enormous, but it has worked.
I have now successfully changed my master LP email account address and can still access my LP Authenticator App and can also backup the codes to my LP account.
In short it all works as before but with my new email address.
Thank you.