Does she have a Certificate of Application for EU Settled Status?
If so this can be used for entering the UK:
https://www.gov.uk/uk-border-control/be ... for-the-uk
Quote:
"If you’re waiting for a decision on your application for settled or pre-settled status
You can still use your EEA or Swiss national identity card to enter the UK if all of the following are true:
you’ve applied for settled or pre-settled status under the EU Settlement Scheme, or Jersey, Guernsey or the Isle of Man’s settlement schemes
you’ve been issued with confirmation your application is valid
you’re not applying as a joining family member"